I agree, get away from IE. It's been dumped. Windows had it's current version frozen too until Firefox and security issues pressured them to update it with XP SP2.
A lot of sites that require IE really don't, they just have bad detection (ugh). As a web guy I really get steamed by such sites. It's not that hard to write compatible web sites - you just have to know what you're doing. Yes, there are going to be Active X sites that will just not work even with a spoof like the Debug menu in Safari, but a lot of them will work.
Also, the 10.3.9 update that just came out boosts Safari JS support and speed quite a bit (~35% increase for page rendering). It's worth getting as it also fixes a ton of other things like the speed of HTTPS sites.