Namco x Capcom is a cool game. My fiance has it, and I've watched him play it a few times. It's awesome.
As for DDR, well, it did make it to the US, actually. Just...in a highly bastardized form. I have the US versions of DDR Max, Max 2, Extreme (UGH UGH UGH WORST DDR EVER) and Extreme 2. Half of the songs are shit and the songs I like are scattered over all four games. I want to import the Japanese versions. :(
I also really, really want to play Ouendan. Sounds like awesomeness.
I would also love to be able to play some Super Robot Wars games, but I can't read enough Japanese yet.
Most of the other import titles that I like have made it here...eventually. Like, Hajime no Ippo: All-Stars was given a quiet US release sometime last year. Also, Gundam Vs. Zeta Gundam had a US release, I've just never seen it for sale anywhere. Plus, who wants to play that crap anyway? I saw some videos of it on Youtube and the dubbing makes me sick. (Yeah, I'm something of a sub elitist, so what? XD)