I've always stuffed the unused cables in the top 5.25 drivebay section. If you were planning to use every inch of your case up and/or were unwilling to tie down cables, then a non-modular would be a mistake. I'm quite happy with my Corsair 650. I'm thinking of using all 4 of my 5.25 bays soon. I might regret being so tight fisted when I'm having to spend a lot of time sorting a proper cable tie down system.
If you are working on your computer innards a lot, then spend the extra on the modular. If not, be a man and get busy layin' cables.
I wasnt. That said I'd have been better with a single Spinpoint, than two previous gen Hitachies in raid.
The TX 750 wouldnt cope with this, let alone the 650. Current gpu scaling tests show a drop in performance sometimes, though I would see games and drivers getting better at >2 gpus. You would be better off selling it in a year and buying a 40nm X2 something. You will need to game a lot in the next 12 months for it to be worth it. The 9800 x2 cost a lot 12 months ago and isnt worth that much 2nd hand now. Same scenario.
) ill stick with the 650 then if in a few years i do go to the crossfiring, ill get in a new psu. If the 750 would have been pushing it, ill take the cheaper psu now, and defintly upgrade later, instead of taking the 750 now, and maybe still having to upgrade the psu later anyway.