Don't be fooled by the Base 55 Defense. With Static, paired with Attract, you can cripple your opponent without breaking a sweat. Not to mention that it has great Mixed Sweeping potential, and good Speed and HP to back up that Defense.
With the right moves, you've got a good sweeper in Raichu. Not the best, by any means, but one of the best ones (Being overshadowed by only Jolteon and Electivire).
Your moveset is almost perfect, but Encore is too risky for a Pokemon like Raichu, who is 2HKO'd by (almost) any strong STAB attack. Replace Encore for Attract. I know this doesn't sound very smart, but it's really the best choice.
If you don't like Attract, then you can also try Brick Break for Screen breaking, Bide with a Focus Sash for (90% of the time, at least :P) a guaranteed KO, or Wish for team support!
Pikachu and Raichu's good attacks (Bide, Wish, Charge, Reversal, etc.) are locked away as egg moves, which is a major downside, but these moves are the key to Raichu's success. =D