burzummaniac said:
It's quite the same. I often play Multiplayer, but I like to have long stories and good replay value also.
Would you be buying them both eventually? If so, then in spite of my love for Fallout 3, I'd have to say get Reach first. If you plan to buy one now and another later, then it's best to let the Fallout game be the one to wait. Fallout 3 was so massive and contained so much content that it was frequently (albeit understandably) glitchy in its unupdated, unpatched, unexpanded form. If New Vegas is of similar scope, it may well be the same. So if one of these games must wait, it should probably Vegas. That way, by the time you get it, the first patches (or even DLC, they rolled out Fallout 3 DLC so fast it was unreal) will be available and the game may be a better experience for it. Meanwhile, you can get to work on your ranks on Reach.
However, if you plan to only buy one or the other, at least for a long time, then I say go for New Vegas. Just because Fallout is awesome.