Help picking motherboard

[R08813]

Well here is what I am dealing with... I have recently bought a Coolermaster Cosmos, a Q6600, a 500W Rosewill PSU, 1GB of Super-Talent DDR2, 2x 250GB SATA, 1x IDE DVD/CD-RW, 2x 120GB IDE HDD's. I have $600 to spend total on o motherboard and video card combination. I am looking to keep it somewhat future-proof as I jumped on the socket 754 bandwagon years ago, followed by pre-AM2 / PCI-E socket 939! So I want to avoid leaving myself behind as much with my next investment. I know the memory and psu will have to go (as soon as I get the money to get some good RAM and a better PSU) because they are both cheap crap. I would like to leave the options open for SLi and DDR3, but neither are 100% necessary if they throw of the "bang for my buck" factor. After all I would like some good performance now in addition to plenty of expandability later on down the road. I am also kind of excited about the potential of eSATA, DX10, and PCI-e 2.0. I am basically looking at the X38/48 chipset as well as the 7xxi. On the X38 side I am looking at a Maximus Formula and a Rampage Formula. From what I see neither supports eSATA, SLi, or DDR3, but I like the overclockability and features! But right now I only have DDR2 and can't afford DDR3. So if I got a board that supported DDR3 it would have to support DDR2 as well. I can't seem to find a decent board that supports both. I also don't want to go over the $300 threshold on the board where it will be robbing me of GPU power. On the Nvidia side the only one that looks tempting is the Striker II Formula which I really like. I like the features and SLi, but again, no DDR3 (which for some stupid reason seems to mean no eSATA too!). Maybe I am focusing too much on the mobo, but I just don't want to be left in the dust again and I don't do too much gaming. For a video card I am looking at a 8800gtx, possibly used to keep down cost. I should also mention that I run dual displays most of the time (unless gaming). One is a 21" CRT and one is a 17" LCD.