When you build your team do you simply use figs to fill out every 'spot' i.e. 1 taxi, 1 brawler, 1 long range or do you build using stricly combos ?

Are you a purist when you build your teams ? (Keepings villains/Heroes seperated or do you mix villains and heroes ?)

Did you find any great figure combos ? Like what ?

Most of the time, I just use the figures that look good for the game. But sometimes, I try to fill out spots and/or combos.

Usually, unless there's special rules, I don't mind mixing the goodies and baddies, as long as somewhere in my mind I can rectify it by comic book standards. IE, I'll put Red Skull and Wolverine on the same team, but Red Skull and Captain America is a no-no.

As for combos, I like using R Thor and V Hawkeye. Either 2 Running Shots or 1 Running Shot and 1 RCEr!

I always build in terms of combos. Every individual figure has its weakness, but a well-constructed team can circle the wagons, so to speak, and prevent gimmicky teams from exploiting those weaknesses. My best teams are those that I've honed into a Swiss Army Knife of Pain; they have some lethal character combo to take down any type of character.
As for mixing heroes and villains, it depends on what my theme is. Sometimes I do heroes or villains only, but I find building on a gameplay theme (such as 'no medics', 'heavy outwit', 'taxi killing', etc.) just as fun. In those cases, I'll team up Superman and Dr. Doom in a heartbeat.
Effective combos? I like carrying Batman with a Doombot, because on a good team that 'bot can 1) move for free, 2) pump up Batman's attack value, and then 3) mimic the Batman ability to stealth right alongside him, so as to avoid Energy Explosion attacks on Batman. I'm also experimenting with using Perplex figures alongside Defenders, JSA and Syndicate members, so I can Perplex up the best attack/defense in the group, then have everyone else share the perplexed value.

yeah last tourney i built an all bad guy team it worked fairly well to0 i dont all ways try to be such a purist though i used

r ultron
e saber tooth
v doc oct
r bullseye
e aim medic
r doombot
r vulture

it went 2-1 only losing that last game to due to time had i one more move i would've won but i lost by 12 points

One of my good combos is:

Annihilus (V) + Boomerang (E)
- Possibility of 5 targets
- Running Shot
- 2 target Energy Explosion
- Via the Minions of Doom ability: You can raise Boomerang's attack to 11, move for free if needed, increase damage via shield ability

Another good one is:
Super Skrull (U) + Dr. Strange (E) or (V)
- Push Strange so he gets enhancement.
- You have a 5 damage running shot which can be perplexed
- Plus should you get into trouble, Strange can phase/taxi Super-Skrull back to safety.

Firelord (E) + Catwoman (V) (I dislike Firelord but sometimes you have to bend the rules)

- Firelord for obvious reasons.
- Catwoman for the Outwit and 17 of defense along with super senses (No outwitter has a defense of 17 for such a cost.)