Circuit City has the Polk R1's for $80/pair and I doubt that you can buy anything better at the price. I have Polk RT35i's ( more expensive) and I'm really satisfied with them. Paradigms are really good speakers too. I've noticed Klipsch speakers going down in price and they are a good choice also.
As for Bose, I'm not a big fan of them but I've listened to my neighbor's 301's ( the latest version IV?) and regardless of the drivers they use, they sound very good. I listened to jazz, classical and some rock music and they definitely sound as good, if not better, than any other speaker in their price range. Perhaps people should stop pre-judging things and just listen to them (like "no highs, no lows, it must be Bose". Well, they DO have highs and they DO have lows and they sound pretty good). I bet in a blind listening tests, most, if not all, Bose bashers out there won't know the difference between different brands of speakers or pinpoint a particular brand out of the lot.
Your sister should go out there and listen to the speakers themsleves so she could buy one that matches her musical tastes. Have her bring it home for a few days and test them out. If not satisfied, bring it back and bring another pair home🙂