I love Grass-types, mainly because of all the interesting designs some of them have. I also feel like Grass gets a lot of interesting type combinations if a lot of recent generations were to go by.
I used to be a huge fan of Grass types, but I've been replaying Emerald recently and I sure am getting sick of all the Roselias and Shroomish(es?), with all those status effects they give my poor 'mons :(