As much as I'd love to say Eevee is the greatest Pokemon since it began, I can't. Actually, saying it's above average in appearance is an over-statement. :\ It's pretty...normal (no pun intended. :P)
And Pikachu? Waaaaay too over-rated (probably one of the reasons I dislike it.) Pichu isn't that special either (definitely not my favourite baby Pokemon, though it is sort of cute. :3) And Raichu is pretty meh too. :\ It just... doesn't appeal to me, and there are much better electric types out there, such as Electivire.
Eevee, on the other hand, has 7 evo... no, eeveelutions (I <3 that word), not to mention that there will most likely be more eeveelutios in the near future (depeding how long the Pokemon francise lives for.) Plus, Espeon, Vaporeon and Glaceon are much, much better than Raichu, Pikachu and Pichu put together. So, Eevee it is. :)