New, white #2 HDPE buckets should all be good, I think. I wanted some fermenters with a bit more capacity than the standard "Ale Pail," which is 6.5 gal. I got three of the 7 gal. white buckets from US Plastics , which can be ordered with lids in a variety of colors, making them easy to tell apart. The lids for these buckets also have a real, functioning neoprene "O"-ring, which means you get a positive seal on the fermenter every time. I got three of these with lids, delivered, for around $32. I have been very pleased with them; the extra .5 gal of headspace doesn't sound like much, but I no longer have any foamouts.
“Malt does more than Milton can / To justify God’s ways to man”
-A. E. Housman (1859–1936). A Shropshire Lad , 1896.