I just collect two armies: my good old (since 5th edition) Dark Elves, the army that really made me join the game and, of course, Chaos Dwarfs! :hat Dunno why I consider only the “evil” version of something previously good… maybe because i like corruption? :o
If I was to create a new army (semi OT) it would be a sigmar themed Empire Army with lots of torches, gritty, dark and brooding with a bunch of mercs to boot. There was an awesome one a few years back in WD, very inspiring.