I've had pretty damn good luck with my 256GB Plextor OS drive for the past year or so, but it's about double the $100 mark. Also have a 64GB Crucial M4 (since relegated to my Win7 tablet) that has not done me any wrong.
This Intel 330 180GB unit seems to be well regarded, at about $160.
You really want to balance cost vs. storage space, with a bias toward storage space. The smaller-capacity units have seen some pretty good price drops, but it does become a royal bitch after a while to have to move/simlink whatever software you're using heavily at a given moment to help maintain space on your OS drive (presuming that you'd want to bother - and I do tend to). In absolute terms, even a 64GB can handle a Win7 64 install just fine, so long as you don't need too many programs resident along with it.
+++ She probably was texting and calling around. Give that kid to a better family. +++