Meh, I have Fallout 3 (for all three systems! Whee!). I love Fallout 3. Between my nine characters I've got something in the region of 400 hour's playtime. Without Mods. Because I don't need to see the Lone Wanderer naked or an irradiated wasteland covered in lush green trees.
I'm going to get Borderlands (Not for all three systems! Whee!). It looks like a lot of fun, but Gearbox have already stated that there's only the most basic semblance of a story which boils down to "Go there. Shoot these. Repeat."
Conclusion? No reason you can't have both. They're not the same game, and I'm fairly certain that Borderlands is going to feel completely different to Fallout 3. But meh, whatever, you've already decided that Borderlands is better...
I'm going to get Borderlands (Not for all three systems! Whee!). It looks like a lot of fun, but Gearbox have already stated that there's only the most basic semblance of a story which boils down to "Go there. Shoot these. Repeat."
Conclusion? No reason you can't have both. They're not the same game, and I'm fairly certain that Borderlands is going to feel completely different to Fallout 3. But meh, whatever, you've already decided that Borderlands is better...