Decent Upgrade for GTX285?

Yep. That resolution is so low that I can basically guarantee you the 7750 could max anything out. It looks like your options are the Power Color or the MSI, and that's it.

Personally, I like the MSI for the aftermarket cooler, but it only has 1GB VRAM, same as the other card.

If you're going to overclock at all, or don't have amazing cooling, stretch the budget and get the MSI. If you're not overclocking, go with the Power Color 7750.

Max even BF3? So 7750 is basically enough and moving up to 7770 would be somewhat like an overkill?

I don't think I would be overclocking it, but if I would, I think I pretty much have a decent airflow, and wouldn't really go for max overclock. Pretty much overclock up to whatever as long as it is below 80-85c max on load.

Edit: System specs
CPU: AMD FX4100 3.6GHz Zambezi
RAM: 2x Kingston 4GB 1333 DDR3
MoBo: Asrock N65C-GS-FX (yeah crappy board but does the job for a board under $50)
PSU: (still to buy) Antec Neo Eco 520W or FSP HEXA HE500 500w

Is your current card dead? Both of those cards are slower then your GTX285. The GTX295 is similar in performance the GTX460/6850. The 7750 would be a step backwards performance wise, while the 7770 would be close with much better power usage. You'd need to go up a lot if you want better then your current card.

i saw a couple of charts that put the 285 ahead of the 7750/7770 at 1900 res. so don't say it's the holy grail.

My gtx285 is still alive and kicking, but 512bit memory bus seems like an overkill for 1366x768 gaming resolution, as far as I know, and what I know is, lower memory bus would barely, if anything at all, affect gaming performance at low resolutions like mine.

So, I was thinking, low memory bus, higher clocks would be optimal for my resolution.

Been checking on benchmarks also that compares these cards, and afaik, the memory bus from the radeon cards (128bit ddr5) are the one killing them on benchmarks for those resolutions (1600 and up), that may be why GTX285 (512bit) are faster on those resolutions. Haven't seen benchmarks for resolutions lower than 1600 though.

But still those cards would barely do any significant performance difference.
You need to get at least GTX 570, 660 , HD 6970, 7850 to actually have any performance difference

Really? I though that disregarding the memory bus, the higher clocks of these radeons would almost max out at BF3 at 1366x768. So I'm basically better off with GTX285 compared to these cards?

Who cares about memory bus, number of shaders, or any other single metric? 512Mb, 480 shaders, 110Gbps of bandwidth. What does any of that mean? Together they give a card its performance abilities, but you can't look at just one and know how it will perform. While a card with 512Mb memory bus sounds great, it could be a dud like the 2900XT.

I could see buying one of these cards if your GTX285 was dead. They would be enough for such a low resolution. But to spend that much money just to save some every month on your electric bill is a waste. Keep the GTX285, buy a new monitor. Your current monitor is the bottleneck in your gaming computer right now. (that we know of.)