I have one for 1920x1080 currently. VRAM usage has maxed out at 1.5 GB for one game only, and that was the original Crysis with maxed settings, foliage, extreme particle physics, and texture mods. All other games, even Skyrim with 70 mods (many of which visual) haven't really pushed a gig thus far. You're totally fine, I'd even say that card should last you for a few more years even with the next gen consoles coming out.
well i have pushed well over 1gb with just skyrims hi-res texture pack, many people with mods push over 2gb. BF3 uses more than 1gb with max settings, Farcry 3 will too. And expect more future titles to use more vram, although it will be another year or two before a game comes out actually requiring 1gb or more to play it.