If you like talking to people about media SF, you might enjoy Redemption. There's loads
of panels, and they tend to be of the everyone-joins-in variety.
If you like dressing up in nice clothes, you might enjoy Confounding Tales -- it's run by the same people who did Convivial a couple of years ago (which I didn't attend, but several people you'll see tonight did, and they can tell you what it was like).
If you like mucking around doing insane things with foolish people, and you like participating in the planning and running of a convention, then you might enjoy Year of the Teledu, which is being planned and run by the membership using an LJ community and a wiki. If you suggest a good idea for the convention, someone will ask you if you fancy putting the item together and running it.
The two Octocons I've been to have been different from each other, but each involved meeting people I only see rarely and a lot of sitting around with beer, talking.
But for sitting around with beer and talking, Novacon is hard to beat. It's very lightly programmed and very unstressful. The hotel has been a bit tatty in the past, but we're assured that it's been refurbished over the last year. If you're able to stay over the Sunday evening, there's a very good meal to be had, with a style of food chosen by the Guest of Honour. This year it'll be traditional Scottish food.
Novacon memberships are £36 by post until October 31st, at which point postal membership closes. You may already be too late to do that. It's £40 on the door, and they're very happy to take on-the-door memberships.
You're going to have a rather harder time getting a room, I suspect. You probably want to ring
Steve Lawson (who is handling membership) to check up whether they're still available. There's a telephone number here