For 40k main army is still Ultras (since 2nd...no idea how many ive now got),
fairly large numbers of guard, orks
DE
small numbers of SW, CSM and tau
Emperors Children CSM
Bad Moon Orks
and in the process of starting a Space Marine army, also have a traitor guard army in the making but progress very slow
Chaos marines - large army (4000 pts +)
Dark eldar - medium army (2500 pts +)
Space wolves - medium and growing (2000 pts+)
Tyanids - medium and growing (enough to field at least 1500 i think - shared army with a mate)
Necrons - small - need to get them back off my godson
have access to:
tau
blood angels
eldar
Space Wolves continually since the start of second edition.
And now eldar. (with a distinctly harlequin look to them!)
Armies that are no longer with us, Orks and chaos marines.
Codex Space Marines (though may switch them to a Blood Angels related chapter).
I have a small 1000 point Tau force to work on after my marines are upto about 3000 points, and about 750 points of Orks, which I will probably not get round to doing for a long time in all honesty, despite quite wanting to.
space marines, space marines, space marines, spikey marines , upset marines, space marines, smurfs
Khorne chaos marines 2000 pts, dark eldar 1500 pts and small deamons 1000 pts.
Witch Hunters (principally Sisters of Battle): 3000 ish points
Ulthwe Eldar: 6000+ points
Khorne Daemons: 1500 points
Back home I had CSM, Daemons and BT.
Here I have Ravenwing, and I'm probably gonna make myself a new daemon army in August. I got to support GW for making new models for a non-human army for once

I have a stupid sized Space Wolf force (about 15000 points)
Some Tau (1000 points or so)
And Dark Eldar (About 1000)