I used to go to a home game, at an estate in Newport. They had a beautiful round table, and it was large enough for 9 players. And I agree with the general consensus that round tables are best for games without a dedicated dealer. They are the most equitable - everyone's position at the table is the same as everyone else's. But the problem with a round table that's large enough to seat 9 players is that the diameter is so large, chips and cards in the middle of the table can be difficult to reach. I'm 6'-1", and I was constantly half-standing to retrieve chips that were lost in the middle, out of reach of other players.
That's what I like about oval tables. Even with a 48" wide oval, things in the middle are never out of reach. Yes, players at the ends rely on the cooperation of players in the middle to drag their pots, but that's true with most home games. And everything is within comfortable reach.
I've never cared for octagons. I'm a little tall, and my knees are always banging against someone or something. I hate that!