From my noob perspective:
Play on the PS3. I hated, HATED SFIV simply because there was no character I truly liked. Now I have quite a few characters that I like and some that have been buffed to relevance. There's also a constant community on the PS3.
Now, if you want a beginner character, don't look further than Ken and Ryu to get the game mechanics down. However, different playstyles might look for something different.
If you like rushdowns, mix ups, stuns, and risk, go for Ibuki, Sakura, Cammy, and Juri. You like "meatier" characters that hit hard, have high life but somewhat limited mobility, look to Dudley, Cody, Sagat.
You know, it's really hard to go wrong in this game. The only characters I'd recommend avoiding are Gen, Dee Jay, and Hakan (they get buffed in AE, though.)
Simple characters to pick up are Cody and Fei Long. Can't think of anyone else at the moment. I personally like characters with Target Combos (Ibuki, Dudley) because it's a bit easier for me.