I used Torterra in Pearl as it's my favourite of the three starters. I hadn't used a grass-type starter before that (well, I had a Bulbasaur that I got from my sister in FireRed but Charmander was my main). Anyway, I really found him useful and even decided to go for another grass-type when I got SoulSilver. I think grass-type Pokémon can be really useful at times and usually they have pretty cool designs. I've recently started to use a Tangrowth at the end of my playthrough and I think it's quite cool. If I start a new game, I'm probably include it in my team.