Steel Battalion is still rare even with the reprints made. The rerelease of the game is apparent in the controller itself -- the original had green buttons while the newer release has blue buttons. The original release will obviously be more collectible/valuable to a true collector and even with the rerelease of the game/controller, there's still not that many in production. It's a truly unique game and gaming experience to say the least. If you have it, take care of it because condition is paramount to collectors such as myself.
I'd love to go into depth about a collector's mentality, but I really don't have the time so I'll just mention a few things. Popular items can easily turn out to be fickle in time and even rare items that were 10 years old and yielded high realizations on the market then can just as easily lose its interest down the road. Quality, scarcity and popularity are all key points in collecting, but you don't necessarily need all for an item to be rare and worth a lot.
Anime cels are an example as I've been collecting them for well over 10 years now. 6 years ago when I was watching Rurouni Kenshin, cels of his chara were very expensive. And yet, he's the main chara in a series that ran over 70 episodes. Not a rare chara in the least as cels of him were prevalent. It was considered by many to be a quality anime and the main chara, Kenshin, was very popular. Cels of him are not rare and yet it's still considered rare considering the market value they yeild. It's rare to own one simply because they tend to be expensive, especially key shots. In the end, however, a item must stand the test of time to see how rare and desireable it truly is.
Here's an example of a few of my many collectibles which are rare for different reasons... (pristine and complete condition for these items) Act Raiser (SNES), Panzer Dragoon Saga (SS), Dragon Force (SS) four copies to collect all four of the available disk cover art, Lufia (SNES), Star Fox Orchestrated OST, Radiant Silvergun (DC), Battletoads (SNES), Demon's Crest (SNES), Earthbound (SNES), Suikoden II (PSX), Rhapsody (PSX), Final Fantasy VI large cardboard store promo, Platinum LE PS2, LoZ WW promo scroll for Nintendo reps, Ogre Battle (SNES), etc.. All are rare, but for different reasons. Some will be more valuable in time while others may decrease in value. Time dictates this in the end, but an item's scarcity (supply), popularity (demand) and quality (true "classic" status) are the main factors.
-Soujirou