Without a doubt, DigitalRev via ebay. Hong Kong based Company, but now with a UK office. I've spent a lot of money with them over the last three years, for me and on behalf of many others (about Â£10,000 in total) and never had any problems with quality or service. They sort any out queries really promptly.
They take paypal with no surcharge, and are 20-25% cheaper than UK prices.
One thing to make sure of though. Some equipment comes from the UK, and some from Hong Kong. For the Hong Kong equipment they run identical auctions in conjunction; some are guaranteed no VAT, some aren't. Basically, they send the package and you may or may not get caught by customs. If you get caught for VAT, which can be a fair whack on expensive gear, they refund you if you bought via the no VAT auction (you scan your receipt and send it, they refund via paypal within 24 hours). The no VAT auctions are a little more expensive, but well worth it; I got a VAT bill on one delivery for Â£112.00 and they refunded it straight away (the no VAT auction was Â£27.00 more expensive).
Hope that helps!