I know people that refuse to play against people with even one squad of long fang too. Doesn't really matter in the end as to what opponents do. Collect the model that is most interesting to you and or fluff. For sheer money sake, a
GK army has the fewest models and can be quite cheap to field.
Space marine models in general are cheap however if you get them used and it is very easy to collect a "count as" space wolf force as well. Can always buy about 10 bucks of space wolf bits from other stores to wolf up your regular marines.
I got a draigo pally force of 2 dreadknights and 2 storm ravens that's about 14 models total at 2000 points

(it's not very competitive but very fun for me fluff wise)
Assault on black reach as resulted in alot of cheap missle launcher marines on the net and elsewhere so you can just as easily make a wolf list that is quite competitive if you don't mind the missle spam.