The All Star Sports and Music Resorts opened in 1994. All Star Movies opened in 1999. Pop Century opened in 2003. This obviously makes the Pop the newest value resort. The room size at all four of the value resorts is nearly identical as are the amenities. All the resorts receive periodic refurbishments that should keep them all similar in "niceness" as well.
That being said, I will say that many people prefer the Pop as their value resort of choice. The primary reason for this is transportation. The Disney buses that serve the All Stars make multiple stops at all the All Star resorts, whereas the Pop buses only stop at the Pop. Of course if you're planning on using your own car as your main means of getting around WDW, then this is a moot point. I would simply choose the value resort that has the themeing you prefer.
There will be special New Years fireworks at the Magic Kingdom at 11:50 on December 31, 2008. Epcot will have a special showing of Illuminations at 11:50 and Disney's Hollywood Studios will have "Lights' Cameras, Happy New Year" fireworks at 11:50. Additionally many of the restaurants throughout Walt Disney World will have special holiday menus and pricing. If you're interested in table service dining on New Years Eve, you should call Disney Dining at 407-WDW-DINE as soon as possible for more information.
You may also want to check
HERE for information on crowd control at WDW on high traffic days such as New Years Eve.