I wouldn't bother with the 1792Mb version. That seems like overkill to me.
Its a tough choice between the 275 and the 260-216. If you're considering SLI, go with the 260. SLI with 260s would cost about $150 less than SLI with 275s.
If you're sticking with a single card and plan on keeping it for a while, I think the 275 is probably the best choice.
With GT300 a few months away I'm finding it hard to be real enthusiastic about any cards that are available now. That thing is going to be a monster.