Lakers (amnesty rule long or short usage LA have 67,6 million including fisher and artest, if they amnesty gasol they would be at almost 49 million so it depends how big salary cap will be)
Clippers (if deandre jordan won't sign as a FA then they could offer Gordon a big qualifying offer and get Howard too, they are in LA and staples center, rivalry with the lakers and a big market)
Nets (biggest market in NYC, if dwill stays it's appealing, or they could sign CP3 if dwill won't sign anything, then Howard goes there, they will amnesty outlaw and they could also offer brook lopez a qualifying offer and have room for humphries too-it's all possible for them)
Knicks (depends on salary cap,they could amnesty Balkman and not opt in on Toney Douglas then they are at 39 million so they got a big shot of getting either Howard or CP3, but they seem to like CP3 more, atleast Melo likes him)
Celtics (We already have a top 5 PG arguably, and the best coach among these: mike brown,del negro,avery johnson,pringles. we can't trade for CP3 in this case since he's also a FA and we surely won't use the amnesty on Rondo or Pierce)
Those 5 teams are Howard's choices as a FA, Orlando are out of the question.
It comes down to one important thing mainly, the cap size, hopefully it's a low cap like 54 mills or less then the Celtics are probably the front runner to get Howard as we could put up a better team with vets like KG and ray on minimum contracts and not guys like juwan howard or larry hughes.