I always liked the Lowdown/ Kelly Cooper Bar and the one that is 1.5 blocks to the west from that, both on Bath Street (City Centre). You can also check the clubs on Sauchiehall Street these are within a 5-10 minute walk from the Lowdown. For a good burger, sarbeni or kebab I would recommend Best Kebab, It's on Bath Street, 30 meters east from Buchanan Street - Just walk under Buchananan Galleries and you're there.
Hmm, so many good memories, I need to go back there next year for a week or two.
As to Sup'Air fields, while I was there I haven't found any, but that was 2+ years ago in the summer. I did meet a guy wearing a JT jersey in Game on Buchanan Street though, but he said there was nothing interesting pb-wise.
I hope things have changed since then as I would love to play some ball with the natives on a walkon day.
Hope that helps.
P.S. You might want to talk to some Clan members, they will be in know about the sup'air fields around there I think.