I try to maintain several:
MAL |
ANN |
A-Planet |
AniDBAniDB shows these stats for my list, whether they're accurate or not

:
Anime 892
Episodes 11149
Files 15105
Size 2083.37 GB
Watched 8380 (75.16%)
AniDB in mylist 11.57%
AniDB watched 8.7%
Time wasted 115 d 8 h
I mainly keep ANN for commentary and the (legit) DVD collection info, Anime-Planet for finding recommendations, AniDB for fansub/rip info, and MAL... because everyone else is doing it? Actually, MAL is good for integrating rewatches into the "time spent" calculations.
Couldn't open the main lists because I need to go get Excel instead of using the crappy MS Works 8 that came installed on my PC. It's a shame the MAL version doesn't include release group info, because I always like browsing people's lists and seeing what groups they go with. I'd imagine yours has a lot of KAA/niizk/THORA and the like.