I actually wrote the bulk of this in 2009, but I'll re-post now that the likely move of Sacramento to Seattle will probably necessitate realignment in the NBA. My theory is that the travel schedule is already unavoidably biased against Seattle and Portland, so you basically must put them in the same division to reduce that.
Anyhow, first things first: In this configuration, East/West does not exist. Conference may or may not exist; but there are 6 divisions of 5 teams each.
Personally, I think radical realignment is the only possibility:
If you move Sacramento to the Northwest, you must either send Minnesota from the Northwest to the Central Division (there is no obvious candidate to leave the Central for another division. You could put Indiana in the Southwest, or Cleveland in the Atlantic, but those are stretches and require additional movement)
Alternatively, Oklahoma City could join the Southwest, New Orleans could move from Southwest to Southeast, Washington from Southeast to Atlantic, Toronto from Atlantic to Central, and then you get to the same logjam in the Central Division (where there are geographically 7 teams if you include Toronto and Minnesota).
Basically, there are no teams who "should" move west (without additional franchise movement. Charlotte or New Orleans relocating to Las Vegas or Vancouver could solve a lot of problems here)
I would then like to see the playoff format changed: The teams with the top 4 records are seeded 1-4 in a 16 team bracket. The next two division winners would be assigned RANDOMLY to the 5/6 slots. The next 10 best records in the league would be randomly paired up, with best record keeping home court advantage. This is part anti-tanking (imagine a Blazers team who doesn't have much reason to compete for the #8 spot, only to lose quickly in the playoffs AND lose their draft pick, but instead might (low chance) end up matched up against the Timberwolves or Milwaukee in the first round) instead of guaranteed date against OKC or SAS, etc.