^For fashion freaks. I don't like the form of that second phone. O.O Also, I don't recommend those phones since you're with Cingular/AT&T. You need GSM 850/1900 on the phone, but those only have GSM 1900. That's just how the carrier works.
Since you didn't mentioned you want the phones unlocked or locked. I'll tell you for both. There are basically no unlocked phones that are that cheap, good, and can use with Cingular. All of the good phones with quad-band are over $200 just about. So, that's basically out of the question.
AT&T carries good phones and you should check them out. Although, that depends if you want to extend the contract or not. The only way you can get these phones that I'm mentioning right now is by extending your contract. You can find out more by asking a AT&T representative.
Sony Ericsson W580
Sony Ericsson W300
Sony Ericsson Z310
Samsung Sync
and lots more.
Well, those are only a few. The prices I'm looking at are online, not in-store so it can vary. Your sister could probably haggle for a lower price. I just recommend that you go to the store and check out the phones that you want, but remember you would have to extend your contract for 2 more years to get them at a cheap price.
To answer your last question. Nokia and Sony Ericsson phones are the best, although the battery life on some Nokias are crap while on the SE phones it's been consistently great on all of their devices. Samsung is pretty good in features, but they've gone overboard with the slimness of phones and now have crappy battery life. I don't like Motorola, but I do admit they got some great phones. Lastly, LG isn't known for their crappy GSM phones. They just suck, but their CDMA phones are completely different; look at the EnV from Verizon, a good phone, and of course they make great phones in Korea along with Samsung.
P.S. If you don't understand some of these terms, look in the FAQ.