It is always citra and cascade for me (I tried citra and mosaic but it didn't turn out as punchy for me) - I really should branch out and try new things though, but it is so damn tasty (and easy).
I'm going to try some more hop varieties too. I usually make 9 or 10 litres and use maybe 40-50 of each (so pretty similar amounts), half at flameout and half as a dry hop. How do you split yours?