RIDGE  CORRECTION:

You can re-order both the lists and the items on the lists. I apologise for this mistake in my previous comment. (Is there no way for me to edit my original post?)  
(Version 1.0)

RIDGE  Plus:

-Small.

-Easy to use.

-Can mark items as important.

Minus:

-If you don`t pay $5 for Checkmarker Plus, you can only create four lists.

-They don`t tell you this on the download page. It doesn`t help that the screenshot on the same page shows a Checkmarker with 5 lists. Furthermore, the download page only says the paid-for version "features new themes and export options", whereas the information button on the widget itself tells you to "buy it now to add unlimited number of pages..."

I hope this was just an innocent omission...

-Would be nice if you could re-order the lists, or individual items on particular lists.

I can see that this program would be really useful if you wanted to keep track of a small number of to-dos in a small number of lists. I don`t recommend it if, like me, you want to add reasonably long shopping lists or something like that.  
(Version 1.0)

STORMCHILD  Haha. I love how "Create new website" is a single task. This is exactly why simple to-do lists don't work. They quickly turn into a landfill for abandoned projects whose steps were never clarified.

Nice design though. I like the way you can grab and drag to reorder items. Would be nice to be able to select multiple items at once to move/delete them as a group, and it seems to me that it would be a lot more useful if it integrated with the to-do items created in Mail/iCal, but it's kind of a moot point as I really don't get any benefit out of lists like this anyway.

Nonetheless, if anyone is just looking for a very simple to-do list and doesn't plan to use it very heavily, this might fit the bill. I don't have any use for it myself, but I always appreciate a well-designed widget. If nothing else, it got me to take a look at Magnetism's other widgets too (and the other ones look pretty nice too).  
(Version 1.0)