Well, even if you're a raiding player clearing heroic mode ICC 25 there will be some really tempting items for you as you level from 80 to 85 in Cataclysm. Items like this Obsidian Executioner, usable at level 81, will certainly be of interest to your 2h melee DPS, while the Decapitator's Razor will draw attention from enhancement shamans, rogues, and perhaps even death knights and fury warriors with the new Single-Minded Fury talent.
From armor to weapons, there's a wide assortment of gear already datamined by the folks at MMO-Champion and I have to say some of this stuff is astonishing. We've talked about gear resets before when previous expansions come out, but when you're looking at such a massive DPS increase between an epic weapon dropped by the heroic Lich King and the crafted weapon you can equip at level 81, it seems like this expansion is really serious about it. Just one example is this level 80 blue tanking hat with 290 stamina on it, a clear sign of the increase in health pools we were told we'd be seeing. The new design paradigm of Cataclysm is definitely showing up in these items. It's safe to say that if you haven't been raiding, you'll probably catch up quickly, and even if you have you'll be replacing items pretty early on.