Well, it's not the best motherboard out there (it's only eVGA's second or third attempt at a motherboard, I believe). It's certainly not bad, though. I've got one that came with my 7800GT as a bundle. Sold the video card to a friend and I've sold the motherboard recently to an Anandtech member. Actually made a profit on the whole deal, but yeah, that motherboard is definately not my first choice. Free is free, and it's certainly worth using at that price point, but my preference far and above is my EPoX EP-9NPA+Ultra (or the SLi version if that's your cup of tea).
Yes, it will overclock decently well. No, it's not a DFI LANPARTY UT nF4 Ultra-D or the like, but it will get the job done, and that's all you're really looking for if you're looking to save money.
Basically, it's not worth buying a different motherboard if you get this bundled with the excellent eVGA 7800GT (and yes, the combo is a very good deal). If you can manage to sell your eVGA motherboard (I sold mine for $80, but it took quite some time and effort -- I bump my FS/FT thread almost exactly every 4 hours), then by all means get something like the DFI LANPARTY UT nF4 Ultra-D or the EPoX EP-9NPA+Ultra, which my personal preference due to it's price point and overclocking ability. Otherwise, stick with your eVGA board. You won't be disappointed.
Hope this helps. Good luck with your new rig!