I'm definitely going to buy a DSi. The only DSi specific games I know I'll get so far are the WarioWare downloadable games. As for regular DS games, I plan on getting Gyakuten Kenji (if it includes english), Chrono Trigger, Kirby Super Star Ultra, Pokemon Platinum, N+, Duke Nukem Trilogy, My Japanese Coach, Metal Slug 7, Mario & Luigi: Partners in Time, DK Jungle Climber, Boulder Dash: ROCKS!, Castlevania: Dawn of Sorrow, Space Invaders Extreme.
I'm also thinking about getting a Saturn. I'd want to get Saturn Bomberman, two multitap and a lot of pads. I'm also interested in titles like NiGHTS, Guardian Heroes,...
As for the "HD" consoles, well, it's hard for me to want one when I don't own an HDTV (and getting a good one seems complicated and expensive) and I'm already buying more games than I have time to play.
I might impulse buy a 360 as they are getting very cheap, but I still have some concerns about the quality of the product and about having to pay for online play. I'm mostly interested in XBLA games: Double Dragon, Geometry Wars 2, Braid, Castlevania: Symphony of the Night. The regular games I'd want would be Tales of Vesperia, Dead Rising (but I hear a HDTV is compulsary for this one), maybe Ninja Gaiden II and Bomberman: Act Zero (to go with my copies of Shaq Fu and Superman 64).
I'll definitely get a PS3 someday, but I don't think it will be in 2009. I'll get it when it's cheaper and in a slimer model. For it, I'd get Metal Gear Solid 4 (I'm hoping a Subsomething version will be release by the time I get a PS3), LittleBigPlanet, and maybe Ninja Gaiden Sigma and Valkyria Chronicles.