MISHA  Sounds like you might want to do a clean install. Spaces shouldn't slow anything down and 10.6 should be noticeably faster than 10.5.8...  
(Version 10.6.2)

MARIE CURIE  How can I config it ?  
(Version 10.6.2)

MISHA  I saw it once under 10.6.1 and a restart fixed it.  
(Version 10.6.2)

RICHARD HALLAS  Yes, I'm getting it ALL THE TIME and I was REALLY hoping that 10.6.2 would fix it. I don't know what the cause is (maybe some third party software?) but it's an absolute pain. A restart fixes it, but it comes back very, very quickly. I'm just putting up with it, but it's a major problem on my machine. A related problem is that some icons vanish completely (i.e. go totally invisible): I just get a blank space in the Finder window, the Dock, or in menus that should show small icons. It appears not to affect all icon sizes, and sometimes the icons may come back, especially if I cause the icons to be refreshed in the Finder somehow. But that doesn't always work. I'm a bit peeved to hear that this hasn't been fixed, as it's a huge visual problem that I'd think Apple would want to address.  
(Version 10.6.2)

UMAROMC  Onyx? Under 'Cleaning'...  
(Version 10.6.2)

MISHA  This seems like a rather esoteric issue, there are not many posts in Apple's discussions about it (I saw yours there, Maulrat). I take it you've tried deleting:

com.apple.dock.plist

com.apple.finder.plist

inside ~/Library/Preferences ?

If you have AppleCare, you might want to give them a shout. I never used to with software issues as I never felt they were very effective, but a recent 30 minute call tracked down and fixed a REALLY esoteric issue that I couldn't find any info on in Apple Discussions (why my MacBook Pro wouldn't hibernate -- it would run itself dead/off when the battery ran out).  
(Version 10.6.2)

DEMORAY  I've been experiencing the exact same issue since 10.6.1.

Like you, I create a ton of custom icons, which makes this minor issue a real pain.

I'm constantly logging out and back in to correct the display, (temporarily, of course).

Here's hoping 10.6.3 addresses this issue.  
(Version 10.6.2)

DAVIDSAN  I have seen the issue when you create custom icons only. For example when using CocoThumb. Icons were updated in SL and now are larger and richer. Icons created using those programs seem blurry. To solve the issue you have to delete all those icons created with third party utilities. Once you do that, the system will recreate the icons and you are good to go. CocoThumb, can be used for erasing the icons too.  
(Version 10.6.2)

MAULRAT  @umaroc: yep that was one of the first utilities I tried

@misha: yes, I deleted those prefs a few times in the past but it didnt help. :( I no longer have apple care either.

@richard hallas: we are definitely in the same boat ... a restart is just a quick cure but it doesnt seem to last long ... and the icon distortion is just so random that its hard to to pin down what the cause may be ... sometimes its just custom icons, sometimes it blurs out dock icons, sometimes (but rarely) it will happen inside an application. The app that it happens the most in with me is Automator, when I first open it and the window prompt asks me to "choose a template for your workflow" a majority of the times the service icon and the Image Capature Plug-In icons are pixelated/blurry/distorted (pick your favorite phrase) .... I also get the disappearing icon trick as well, once again mostly a random issue but a pain none the less.  
(Version 10.6.2)

MAULRAT  @Davidsan: Thats what I'm doing right now ... unfortunately this is probably going to take weeks to do because I have upwards of 100,000+ custom icons ... I'm just using the Zap Resource Fork script to wipe them out ... the issue is with the folder icons (as opposed to .icn files) I have to recreate each and every one of them ... yuk ... on the plus side though it seems to be freeing up tons of space ... 100 GB so far ... thanks.  
(Version 10.6.2)

BILLEARL  Same problem here with date/time and airport menu. Some sort of conflict I suppose.  
(Version 10.6.2)

ROWSDOWER  Good to know it's not just me. I'm sure someone smarter than I will come through with the solution sooner or later. :-)  
(Version 10.6.2)

YAZSOFT SUPPORT  Try downloading the 10.6.2 Combo updater and installing that.

It usually addresses these types of issues (assuming you have no incompatible software installed on your Mac).  
(Version 10.6.2)

COMMUN5  No similar problem on an early 2008 MacBook 2.1ghz C2D 2 GB RAM done through Software Update, so it must be specific to your machines. I agree with the Combo re-update suggestion.  
(Version 10.6.2)

ROWSDOWER  Yazsoft Support: Try downloading the 10.6.2 Combo updater and installing that.

I tried, but no difference. Must be a software conflict.  
(Version 10.6.2)

YAZSOFT SUPPORT  ROWSDOWER:

Try this:

- Create a new user account on your Mac

- Log into that new user account

- Do you still see the same quirks?

If you do, the bug/conflict is at your system level. If you don't, then there is something specific to your user account causing the glitch.  
(Version 10.6.2)

ROWSDOWER  I tried booting into Safe Mode, same problem. I'll try the "New account" approach.

Thanks for the tip!  
(Version 10.6.2)

BILLEARL  I found the fix, at least in my case. I suspected Spotless because it messes with Menu Items. The fix is to open Spotless, select Preferences from the Spotless menu, select Spotlight Menu, then toggle the "Hide the Spotlight Menu Item" checkbox.  
(Version 10.6.2)

ROWSDOWER  BILLEARL: I found the fix, at least in my case. I suspected Spotless because it messes with Menu Items. The fix is to open Spotless, select Preferences from the Spotless menu, select Spotlight Menu, then toggle the "Hide the Spotlight Menu Item" checkbox.

That could be my problem. I'd removed my Spotlight icon using some Terminal commands, but I don't remember what they were. :-O

I'll give Spotless a try. Thanks!  
(Version 10.6.2)

CLAKES  Problem with the Spotlight, Wi-Fi, Bluetooth and Date&Time (well, I don't care much about this last since I use MenuCalendarClock but..) menubar icons disappearing persists on my latest generation MBP running even after repairing permissions and reverting the terminal commands I used to remove the Spotlight icon:

$ cd /System/Library/CoreServices/

$ sudo mv Search.bundle/ Search2.bundle/

reverted using:

$ cd /System/Library/CoreServices/

$ sudo mv Search2.bundle/ Search.bundle/

Link to the tip I followed:

http://superuser.com/questions/32593/remove-spotlight-icon-from-the-menu-bar

Functionality is preserved at least, but hey... I need those familiar icons up there. =\  
(Version 10.6.2)

JIMBLU  what happens when you double click them is this folder?: HD/System/Library/CoreServices/MenuExtras  
(Version 10.6.2)

CLAKES  @JimBlue: tried to launch'em from the folder you named.

The menubar just flickers, but no icon is appearing. There's just blank icons which can be clicked with no result (no menu, just the menu selection color switch)...

Gah! No luck.  
(Version 10.6.2)

JIMBLU  they are blank on mine too, but if i double click em they show up in the menu bar. i just wanted to make sure if one went straight to the source that it would not help. sounds like something within the system files is messed up or corrupted. -- sometimes when i get lost and don't know how to fix something i carefully -- carefully-- run the safest stuff with Onyx -- or cocktail but i think it costs too much. i haven't installed either yet because i haven't needed them.  
(Version 10.6.2)