I religiously played the first two games when I was younger. Brawl was absolutely terrible for the many reasons that have already been discussed to death, so I didn't play that one for long. Now, I play Project M a lot, as it is easily the best one to date. I simply can't go back to Melee after PM.
With the new one, I have no idea who I'll be playing. I have no attachment to any of Nintendo's characters, so I'll just pick someone who's good and that I find fun to use.
I'll be playing on 3DS, sadly, but there is a chance I'll get a Wii U if the game is actually good this time, or if they do a Smash Bros. console bundle at the time of release.