I still dont see an H61 motherboard as being as horribly limited as you say.
a $500 price point is inexpensive enough that you're really goibng to just replace the whole system in 2-3 years anyway.
Still I see plenty of upgrade options for a H61 board.
You can upgrade to 2x8GB RAM (16 GB)..yeah you don't keep your existing 2x2GB, but so what?
You can add an SSD, you even have 2 SATA 3 ports to plug one in...you can't do a RAID, but that's not a huge loss.
you can add up to 2 more hard drives in the SATA 2 slots, assuming 1 for your starting HDD, and 1 for the DVD burner
The 2100 can be replaced with a 2300, 2400, 2500, and 2600. Possibly it will handle the new i7-3000 series of 6-core processors and Ivy Bridge.
The single video card slot will take a 7000 series card just fine, though admittedly the case (Rosewill R102) is limited to cards of 9.25" or less. in the current generation, this means you have to max out with a GTX560ti. *Horrors!*
what is missing in the way of upgrades?