I just spent a vast sum of money with Up1. It's been recommended to me by a lot of people, so I would use them. You don't have to pay customs or anything either, it's shipped from the UK.
EDIT:
www.up1.co.uk
EDIT2: Actually, I'll list what I bought : P
Black Lagoon 1 + 2 special editions
Ergo Proxy 1 + artbox
Tenjho Tenge 1 + artbox
Last Exile 1 + artbox + limited edition extra
Ah My Goddess 1 + artbox
Aquarian Age: Juvenille Orion 5 + artbox (manga)
Beck 1 + artbox
Texhnolyze 1 + artbox
Eureka Seven 1,3,5,6,7 special editions
Mai Hime 7 + artbox
FLCL Ultimate Collection
Hellsing Ultimate 1+2 special editions
Gungrave 1 + artbox
Kamichu! 1 + artbox
Kyou Kara Maoh Season 1 volume 4 + artbox and Season 2 volume 1 +artbox
Melancholy of Haruhi Suzumiya 1 + 2 special editions
Read of Die 7 + artbox + figure
Rozen Maiden 1 + artbox
I would have loved to order Gankutsuou 1 + artbox but it's out of print -.-
Same with the Fate/Stay Night 1 + artbox (which only came out 4 months ago!!)
I just hope lots of those older releases are actually able to be obtained..
I should have ordered these artboxes a long time ago..
When I get some more money together (when I get a job after the exams), I'm going to buy the two 12k boxsets, and see if I can find the 'out of print' Card Captor Sakura box sets, and try and find the GITS:SAC volume 7 special edition (that play.com messed up for me last year). Damn there's so much stuff O_O