What is your opinion of this as a light gaming laptop?

That is actually an excellent mid-range gaming rig. That particular graphics card is a good one and can actually handle modern games like COD mw2 and Battlefield 2 at a resolution of 1360x768 (recommended settings). It can handle higher resolutions of course, but you might need to tweak it based on the game. Given the games that you mentioned, this graphics card would own on the highest possible settings. As for your hookup to the large monitor, running these games at 1920 * 1080p wouldn't be a problem and you likely will not experience lag. I don't think running it at higher resolutions would be recommended though, as the card is limited in it's capabilities. I actually have one it's predecesors, the GT330 m, which works perfect for my needs and is capable of running Crysis on medium to high settings. The other specs for this xps are solid and I think it's priced well. I'm not particularly a fan of Dell, (in fact I don't like them much), but I make an exception of their XPS line of gaming rigs. Go for it.