I've always preferred the Battletech designs myself, but I definitely like the heavier models that can run up in the face of your alpha strike and blow you up anyways. I used the Loki and the Awesome a lot in MechWarrior 4.
Still, mechs are a bit ridiculous no matter how they look. I think personal exoskeletons like the Battletech Elementals or the Mobile Infantry suits from Starship Troopers are a lot more believable in sci fi.