Safari has a serious memory leak in Lion, that and the lack of extensions make me wonder why people would use it.
I use Firefox mostly because the AdBlock+ extension actually blocks video ads properly and from any website. The Chrome version doesn't.
I have my own HOSTS file which pretty much blocks every ad under the sun. Gives me more direct control, which I prefer.
I'm a tremendous "abuser" of browsers, generally. I find that despite my best efforts, I often end up with 20 or 30 windows open, and close to 200 tabs (I know, I'm crazy...). Needless to say, I end up with browser crashes fairly often. I end up using some of the session manager extensions in Safari, like "Sessions" and "SafariRestore". Are there similar extensions available for Chrome?