If ASICs do take over Scrypt mining later this year, I think it will basically put an end to all the Scrypt coins except LTC and DOGE. These are the only ones that have a substantial enough user base. Everything else will be dumped to oblivion via multipools and never have a chance to get off the ground. We're already seeing this start to happen due to the increasing use of multipools, and the advent of powerful ASICs will complete the process.
It's hard to say what it will mean for pricing. On the one hand, LTC and DOGE will become a lot harder for the average user to get, as a result of increasing difficulty. On the other hand, a lot of the ASIC miners are going to want to dump their LTC/DOGE for cash (or at least BTC) immediately. This could result in the price actually dropping, not rising. And don't forget that a lot of people like LTC and DOGE specifically because they are more decentralized and egalitarian than BTC currently is. If you can no longer get into the Scrypt game without $10K of specialized hardware, parts of the community might decide to move on to something else instead, thus depressing demand for the Scrypt coins.
Many of the GPU miners will want to move on to altcoins that use a different algorithm, one that still hasn't been updated for ASIC. Vertcoin, Maxcoin, and Tenfivecoin might see a boost as a result of this. We'll probably see a whole bunch of new knockoff Scrypt-N (or Scrypt-Jane) coins, and then multipools. The question is whether anyone is going to buy. As things currently stand, most of the altcoins are only of interest to miners and day traders. From what I can tell, only BTC, LTC, and DOGE are ever actually used as a medium of exchange. There may be some exceptions, but not many.