I like the Ultimate approach so far, I don't mind paying a little more to get a better arsenal with a character. I don't see the Arnold rereleases tempting me as I don't care about the leg articulation, so it's new characters/versions that I'm after (but it's a very smart way to get the figures back out there, and he's always good to anchor a line).
My top 3:
1.] 'Terminator 3' T-850 (I need an updated T3 Arnold in my life. Perfect fit for the ultimate line. The higher price point could allow for his coffin and weapons.)
2.] 'Terminator 3' T-X (The added articulation would work well for this character, and she has a good amount of interchangeable parts.)
3.] 'Terminator' Kyle Reese (I'm glad just to own him, but I think he would benefit most for an updated sculpt as he wasn't quite nailed the first time.)
I like a Future Kyle too but with so much tooling and not a lot of accessory options, maybe he'd be better served in a 2-pack with an endo or a future John.