I am looking to upgrade my computer (keeping only my 9800 GTX+ and antec 300 case), don't do much gaming, but do a lot of development (web mostly), photoshop, etc, and want to spend around $600-$700. I work from home so speed and reliability are critical.
I am not interested in overclocking, so what processor/motherboard is the best bang for the buck? Is a sandy bridge setup worth waiting for if I don't care about OCing?
Waiting for the Sandy Bridge is best, because you would need to overclock the current AMD chips to get close to the SB. Clock for clock at default speeds and price they are the best bang for the buck currently. If you can wait a little longer, AMD will have a new chip out called Bulldozer, but as of now... nobody knows what it's performance and cost will be.
But if you can get your hands on a 2500 or even the 2600, you won't be disappointed. There really isn't a need to look at the older i5 or i7 because the socket 1156 and 1366 are going to be phased out. So the 1155 SB will also have a better upgrade path in the future. And the older i5 and i7, and especially high end Core 2 Quads still cost more than the faster Sandy Bridge chips.