If you're going with Lombre, I recommend doing this:
1 - Breed a Lotad that knows Razor Leaf (egg move)
2 - Have it learn Giga Drain, if you want an optional choice Water pulse, both learned via TM. TMs are 3-Water Pulse and 19-Giga Drain.
3 - If you spring for Water Pulse (TM) or Hydro Pump (Level 49 of gen 3), get Rain Dance. Both of Lotad's/Lobre's/Ludicolo's normal abilities boost in rain. I prefer Rain Dish of its healing abilities.
4 - Train Lotad/Lombre with Macho Brace for a better Pokemon
5 - Once you get the desired goal evolve Lombre to Ludicolo.
In other words, the end result would show something like this:
Ability Rain Dish
Razor Leaf
Rain Dance
Giga Drain
Water Pulse/Hydro Pump
This may not be the best, but I hope I helped.