At this point, you're better off waiting *IF* you don't mind paying the higher prices for the upcoming new Profile 2.0 players. Alternatively, you can also consider the Panny BD30 (Profile 1.1) or the PS3/40GB (Profile 2.0 after latest software update plus SonyStyle.com and their retail stores are still offering their $100 back deal w/ new Sony credit card right now).
I would just pass on the old Sony S300. It's only Profile 1.0, IIRC, and almost certainly not upgradeable to 1.1 (nor 2.0), and it's a rather sluggish player.
_Man_