A new favourite is Bibs N Bots. They have a lovely range of products, some good sales, and fast, friendly customer service. I've just bought some gorgeous nappies from here which were dispatched very quickly and arrived with freebies - some gorgeous lemon lipbalm, 2 cotton/velour washable wipes and a little choccie! I love thoughtful little touches like that and you can always buy my loyalty with chocolate!!
I LOVE Wee Notions - not ordered from there yet due to lack of funds but loads of people I know rave about it and I've spent hours drooling over the website lol.
Cheeks & Cherries are fab, I recently bought a limited edition Itti Bitti D'lish from them and the customer service was brilliant, they couldn't help me enough. I'm new to cloth so was asking a LOT of questions and they replied to emails really quickly, didn't mind answering all my questions, and were just generally really lovely.
Another cheeks and cherries fan here ... love that website! I also visit www.fillyourpants.com quite a bit, v. good customer service. Of course, I am addicted to weenotions and have just ordered my 2nd custom nappy. I think I have an addiction! x