I've actually never heard of those before. Sennheiser releases a million headphones a year so it's hard to keep up. Anyway, they look like the HD212s of old, which were supposed to be worse than HD201s, which I DO have (verdict: not very good), so I wouldn't expect much from them.
Anyway, some qualities of the HD280 - they're VERY good at isolation (almost as good as Bose QC2s, which are active noise cancelling - 280 Pros are passive!), but sound a little bit tinny and harsh, at times (especially with full music, like heavy rock). They lack a little bit of bass, but they are very good at showing detail, which is good for a gamer.
Unfortunately, the cheapest HD280 Pro I could find is
$85 shipped from Buy.com. I remember there was a slickdeals posting about the HD280 Pros (I think for $60-70 shipped), and I'm pretty sure a friend of mine got his for $80 or so.
If you're not convinced, look through
Headroom's listing of closed headphones. I kinda forgot that you could use supra-aural headphones, too (which are cheaper than full-sized headphones, but aren't as comfortable). If you don't mind pads that sit on your ears, the AKG K81DJ are a really good choice as well (except that they are uncomfortable as heck, especially if you have a big head).