JEFF WRAGG  I maintain lots of macs and these betas have done very well. Just yesterday onyx cleared up a big problem for me on a snow leopard MacBook pro.   
(Version 2.1b4)

JEFF WRAGG  It works fine on my two Snow Leopard machines. So the problem must be elsewhere. Maybe reinstall both Inkscape and X11? Note that xquartz 2.40 does not work on snow leopard. Use the apple version 2.3.4 installed by SL.

Can you describe your problem more fully?  
(Version 0.47pre2.2)

JEFF WRAGG  I run Inkscape on many machines, and we don't see this problem. Although I run X11 version 2.3.X

Inkscape is quite popular with my students, who find it appropriately powerful, and well priced.  
(Version 0.46.3)

JEFF WRAGG  We have used TeXShop extensively in our department (Physics & Astronomy) for a couple of years now. Students and faculty love it. We use the current betas, (up to 2.1b7 now) and all is well. We formerly used iTeXMac, but switch to TeXShop because it was better. Not sure if that is still the case, but we are not motivated to switch back for now.  
(Version 2.10b7)