Some really great labels there. I'll always have a soft spot for Vipco, that was the first label I started collecting films from in my teens, and, in all fairness they released some great films (maybe not the best quality etc.) but they made a lot of obscure and ex-nasty titles widely available and I've got respect for them for that. Made my life easier when I was younger aswell.
Obviously I love Shameless so I wont dwell on that one too much. They are my favourite though, the time and effort put into restoring picture and sound and the releases in general is top notch.
Although I wish I owned more of their titles Blue Underground are another great label as are ABUK and ABUS. I quite like Tartan aswell, they're Asia Extreme dvd's were great as were they're Grindhouse releases. I'm kind of spoilt for choice