The
Corsair TX750W for $109 after $24 MIR is a fairly cheap 750W PSU with great power, efficiency, and reliability. It will most likely run a GTX 260 setup, but the chances of a successful build decrease greatly when you start talking about a GTX 280 SLI setup. If you really, really want a 280 SLI setup, you'd be MUCH better off with an 850W PSU; the lowest price for which is
$140.
For the MB and RAM, There's an NCIX sale now, and there's a
eVGA 790i FTW + 4GB DDR3-1600 bundle for $270 if you buy it before they sell out. Unfortunately the RAM is some cheap Aeneon stuff, the quality of which I cannot comment on; however some reviews I read are positive and others...not-so-positive. They should last you for a fair amount of time, at which point you may have the funds to invest in some faster, higher-quality stuff.
The e8400 for $200 is a good price. It's hella-overclockable (should you decide to later) and comes with an already-fast clock speed. Unfortunately it is only 2-cores, and it might age quickly depending on when more games start coming out that better support quad-core over dual-core. For now, I would futureproof your build by spending $40 more and getting a Q6600, which is also hella-overclockable (should you decide to later) and is quad-core, but unfortunately has a slightly slower clock speed. If you do decide to OC, I would get the Q6600 because not only is it quad-core but you can easily bump it up to 3.2ghz, maybe 3.4ghz with sufficient cooling.
The GTX 260 is just the regular 65nm one, same as when it first came out, but the lowest price I could find is $200 after $20 MIR at
NCIX. But then, for the price you originally stipulated ($256), for $14 more you can get the
GTX260 Core 216 which uses a bit less power, and has more performance for the price you pay (performance is similar to that of a full-on 280). In effect, if you are completely ready to pay $256 for a GPU you may as well spend $14 more and get the 260 Core 216, but if you want to save that $56 and get a regular GTX260, then the choice is yours.
For the RAM, if you decide to go with the combo then all your bases are covered. However, if the RAM breaks or you don't like it, then I think that you could do just as well with
GSkill 4GB (2x2GB) DDR3-1600 for $100. If you look on Newegg they got a bunch of nice, fairly cheap DDR3 kits, and if you want DDR3-1333 or DDR3-1066 to save a bit of cash.
If you decide not to go with the bundle, then you should think about just getting a regular S775, DDR2 board with SLI. Two such boards are the
750i SLI, for $137 after $20 MIR and the
750i FTW for $165 after $30 MIR. Both will suit you just fine for this build, and as far as I know they're in a small group of LGA775 boards that can actually do x16 x16 SLI and not Crossfire. Ask me if you change your mind and want a Crossfire board and setup, because then there's the 4870 which is on sale all over the place, and yeah...
Anyway, if you get the FTW or a comparable LGA775,DDR2,SLI board, then of course you're going to need DDR2 RAM. There's a
4GB OCZ DDR2-1066 kit for $45 after $25MIR right now, you could pricematch it at NCIX and then buy it from there. Then there's some
GSkill's at the same speed for $62 flat, and then of course there's a whole bunch of kits in between and past the GSkill's, but $40 to $70 is the best price range for a 4GB DDR2-1066 kit.
EDIT: I forgot to add that if all you'll be gaming on is a 19" CRT, you won't need a GTX260 for awhile, the GTX260 is waay overkill, especially for just a regular 19" CRT. You'd be far better off getting a 4850, 4830, 9800GT, 9800GTX the most you would need for 19" resolutions, unless that thing can do 1680x1050....
Also, you shoud consider getting a HSF. Theres two cheap approximately $40 ones, the OCZ Vendetta II, and the Xigmatek HDT-S1283. The Vendetta II performs better and I think if you look is slightly cheaper than the Xigmatek, but I'm not sure.