Heh...I was always one for a themed team, myself. In Diamond right now I have a steel team I'm working on:
Skarmory (Steel/Flying) NO ground weakness, only really hurt by fire and electric. Usually goes first, as he's one of the fastest steel types. He has a nice range in his moveset, with dark, rock, flying, and steel.
Steelix (Steel/Ground) Lots of weaknesses, but with Thunder, Fire, and Ice fang, and earthquake, he can take just about anyone down. Really good defense too.
Empoleon (Steel/Water) Very good special attack, really good defense, Surf and Ice Beam take care of most stuff, Shadow Claw for any pesky ghosties or psycics.
Lucario (Steel/Fighting) Drain Punch is my friend with Lucario's very high attack and great speed. Give him Water Pulse and he can cover his Fire and Ground weaknesses. Rock Slide or Stone Edge make the flying foes back off. Only problem is he has one of the lowest defenses of the steel type.
Scizor (Steel/Bug) Fast with decent special attack, mostly use him to get out Toxic. Bug moves are great for the grass types and the psycics. X-Scissors for the win.
Bronzong (Steel/Psychic) With Levitate, Bronzong only has a fire weakness. I really wish you could teach him any water type moves, but you can't. His ridiculous defense makes up for it though. Give him Dream Eater and he's even more ridiculous.
It's a good team that easily beats the opposition. Others I thought about using:
Aggron (Steel/Rock) His beastly attack and really great defense makes him a prime candidate. He can also learn just about ANYTHING. Seriously. Like 70% of the TMs work for him. Problem is he has severe Fighting and Ground weaknesses (X4 for both) and his speed is atrocious.
Metagross (Steel/Psychic) Almost made it on my team, because he's a great pokemon with really good balanced stats. He learns a lot of great moves, but I chose Bronzong over Metagross for my psychic type because of Bronzong's superior defense and Levitate ablity.
I like my team.
