re Islay, I'd recommend planning to have lunch at Ardbeg if/when you visit the three distilleries to the south of the island, they have a good new-ish cafe. I don't think Laphroaig and Lagavulin do. As for tours, I've done quite a few over the years but none on Islay, so can't recommend any I'm afraid. Most of the disilleries are very generous with tasters. I enjoyed a proper tasting seession at Bowmore where I stayed last time I was there. Most of the pubs and hotel bars have outstanding whisky selections
The whole place is geared up for tourists, be sure to eat lots of langoustines and scallops etc.
As for beer on Islay, it is rather lacking. The only microbrewery on the island is not very good imo and most beers in pubs/hotels still tend to revolve around the Tennents/Belhaven/Guinness trifecta. But I wouldn't worry too much as you'll be there mainly for the whisky :) Would definately recommend visiting Fyne Ales as mentioned earlier in the thread.
In Glasgow some decent pubs with good beer and whisky are the Pot Still and the Bon Accord. WEST is well worth a visit imo for German inspired beers and it has nice food in their beer hall. Other pubs with good beer - Three Judges, The Lauriston. Modern beer destinations - Brewdog (2 locations) Inn Deep (williams Bros own this) 6 degrees north.