i wouldnt go so far as to say the biggest... I my self did that because i didnt know...
But I will tell you from my experience and from what i have heard bigger has some advantages... It is much harder to overfeed, they wont go rootbound, less likely to get root rot, etc... Negatives: heavy as hell, more space-maybe need more light..., more area for bugs. Positives outweigh the negatives...
I have also heard you need a gallon for every vertical foot, or a maximum of 4 gallons. So if your gonna do some SOGing or LSTing than you know you can get away with smaller containers. But otherwise go ahead and get like a 4 gallon or bigger pot, thats what i have and i am glad.
A couple recommendations though:
If you can buy square pots, they fit together much better- and free up space when it is available.
And Make new and good dirt- I dont know what you have, but invest in a cheap mixture such as the one I recommed and you will be happy.
Both of these suggestions I hadnt been given and failed to do, and wish i had, especially the later, a good soil mix is critical when you have to flush your plants- that requires running lots of water through your plants before harvest to remove impurities- and if your soil is not easy to drain its a muddy mess that is dangerous for your plant- which is what i may be faced with...
So in telling you that I will give you a soil recipe i have collected and plan to use for my next grow... Its cheap and available-
I cant remember who I got this from- but Its not mine and I found it online- not trying to plagiarize if this is someone reading this lol...
"To all my fellow growers. Never use anthing but your own soil mix. Wal-mart sells Super Soil (basic soil) they also sell perlite (white balls for spacing). I went to my local pet supply store and got bat guano (10-3-5) then i got earth worm castings (12-6-3) for a 100% soil mix you need a mixture of 50-60% super soil, 15-25% perlite, 15% worm casting mixed with bat guano, then i got 10% sand (also sold at pet shop) you could use concret mix, but sand is prefured, and oh yeah! dont use beach sand, it contains salts....always spray your roots with nutes when you transpot your stuff.
Just a thought, G'luck
P.S. I also had like less than 5% pre-mix (found this at Wal-mart, but then i couldn't find it anywhere but Pet Stop)
And if the (%) thing throws you off, den start off with cups (out of ten = 100%)"
Sorry for the length, but I wish someone would have told me, hope it helps.
OB