To be totally honest im a pretty competent programmer, yet ive never actually written a full game.
My attitude is :- If theres no point, dont bother.
I NEVER liked space invaders or pacman and I cant see the point in making a game that I dont like - one of the cheif things about making games is your making games you like because you like making games.
I spend my time writing small programs that help me write games, or i start with a 'rough' copy that fleshes out the main parts of a program/game(eg controls, camera etc) before moving on to a proper version.
I make thing such as underwater effects and special fx like bullettime, but im not using them till i get dbpro.
Id go with 3d if your doing a big project, it makes more sense to take advantage of the engines power. If your doing this just to learn, go with 2d.
"It's amazin' what you can do with a computer and access to t'internet"