A couple of spiffy ways to Mac-ify FireFox-

[madmaxmedia]

I have 1.5 running, so have problems getting extensions and themes running on it. But these 2 are pretty nice-

Firefoxy- makes widgets (buttons, drop down boxes, etc.) look Mac-like.
http://www.amake.us/software/firefoxy/

Brushed Theme- I still like the old brushed metal, this theme is pretty good-
http://temporaer.net/open/themes/

[wordmunger]

Are there any extensions that make it stop crashing my computer about 15 - 20 percent of the time when I put it to sleep?

[madmaxmedia]

I don't have that problem, although I do get occasional crashes, mainly when I do a couple of things at once.

I use it though for the extensions...

[alex_ant]

Try the GrApple theme if you don't like the brushed look. http://www.grapple.net.tf/