Right, I re-checked that. For Skyrim it's only a issue if you fiddle around with ini settings (grids) or texture mods. With both you can even kill a 4GB setup. In BF3 it seems to be a general problem.
Might as well have a go at explaining that.
Their naming is usually pretty straightforward in the desktop space. Each generation (denoted by the first digit), they design a few GPUs of varying size and ability. The best GPU gets the x9xx model numbers, the second-best the x8xx numbers and so on.
Each of these GPUs are usually released in two versions, one fully functional and the other toned down in one way or another. They get the xx70 and xx50 numbers, respectively. Sometimes, they add more versions and they get either xx30 or xx90 numbers - xx90's can sometimes be nerfed versions of the GPU above (for example, a 6790 is a crippled 6870). For top-end graphics cards, the xx90 number is used for dual-GPU graphics cards, so eg. a 6990 contains two 6970 GPUs on one card.
In laptops, it's my impression that this fairly straightforward system falls apart with much of the same confusion Nvidia employs (they just do it on desktops too from time to time). Laptops really are a pain to shop for if you actually want to have a good idea what you're getting. Probably because most laptop buyers don't have a clue anyway, so the retailers just give them some fancy but rather useless numbers and buzzwords.
Skyrim ran much more smoothly for me when it was using 4GB of RAM even though I wasn't using any mods or anything.
Eh, from the desktop perspective I can't say I've had a bad experience with them, seeing as mine is still doing well after three and a half years. Of course laptops are another matter entirely.
I'm not sure if you are into spending considerably huge amount of money for entertainment but I think Asus G74SX would be a good option. Its price may reach up to $1,700 but I think it's worth it.