I have a list around here somewhere on disc that I've failed ot keep updated over the past couple of months, but here's a rough idea:
Still Working On
Uncanny X-Men - 102, 117-118, 122-126, 128-139, 141-453 (current)
X-Factor - 1-6, 18-23, 25-27, 36-39, 60-62, 65-149 (end)
Excalibur - 1, 11-18, 21-22, 26-28, 71-102, 112, 120-125 (end)
Wolverine - 1, 6, 60, 62, 72-184, (volume 2) 12-23 (current)
New Mutants - 1-3, 14, 23, 26-27, 38-44, 59-61, 70, 72-73, 79, 87-97, 99-100 (end)
Ultimate X-Men - 2-53 (current) (so close!)
Mystique - 1-20 (almost current)
Emma Frost - 1-16 (almost current)
X-Men Unlimited 1-38 (missing a few on the tail end)
Complete Sets
(New) X-Men - 1-165
Cable - 1-107
X-Force - 1-129
Generation X - 1-75
X-Man - 1-75
Mutant X - 1-32
Bishop The Last X-Man - 1-16
Gambit - 1-25
X-treme X-Men - 1-46
Warlock - 1-9
Weapon X - 1-28
All 34 AoA comics
Well I'll stop there. You can include in there pretty much anything that's come out over the past 10 years that I didn't type in as well as about 100 to 150 limited series issues and one shots. Counting only those on the list there's around 1600 comics give or take. That's only a part of my comic collection. Other people have a lot more but I'm proud of it. After counting those if I had to guess at the number of comics I have I'd have to guess around 5000 comics totle.