I buy regularly from Northern Brewer. I like the ingredient kits, they virtually have the whole bill of goods listed. It gives you a good of what you are buying.
http://www.northernbrewer.com
I also like Williams Brewing occasionally.
http://www.williamsbrewing.com/
Same goes with Midwest
http://www.midwestsupplies.com/
I haven't tried More Beer or Austin, both have good sites.
Austin - for beer kits and especially clones. Not so good visually very few photos if any other than icons for clicking.
More Beer - a good for a sight w/ info and lots of photos.
I usually like to shop close to home mainly for the cheapest shipping.
