I actually use an online todo list so I could copy-paste everything here if I wanted... but here are some of the things I will be trying to do soon:
First, a few coding bits behind the scenes to straighten a few things up and make things faster. I turned on "caching" yesterday which should make pages load a lot quicker.
Fix the news on the front page asap, the home page is displaying fine but page 2 doesn't work, nor the "continue" links.
Fix the egg moves for later evolutions (e.g. Golduck doesn't show any egg moves, but it should show the same as Psyduck).
Show EVs by pokemon in the pokedex.
List of members online in shoutbox and maybe on the main site too.
More/better location data and a way to look at each route individually to see what pokemon are there.
Moves for HG/SS where different, plus older generations.
Add 'special moves' section, e.g. the extra moves learned by Rotom formes, those Pikachus with Surf/Fly etc.
More detail for moves (ongoing effort - I did several yesterday after seeing the question about Dive).
Some basic text about each pokemon, including name origins.
More sprites, from older games.
A page about status conditions (including things like confusion, infatuation).
Stripped-down mobile version for fast access to some info.