I'm just recovering from flu and this topic comes up - I couldn't face any beer the way I feel at the moment.
Anyway here goes -
Stouts - Sam Smiths, Guinness and Gillespies
Ales - Tim. Taylor's Landlord, Green King Abbot Ale, Caledonian IPA and 80 Shilling, Pendle Witches brew, a local brewer, Marble, produce a ginger flavoured ale and a personal favourite, a small brewery in Plymouth called the Sutton Brewery and I pretty much like all they brew
Lagers - Loads of Czech lagers, Gambrinus, Radegast, Staropramen, Pilsner Urquell - you can also get dark lagers , Krusowicz (spelling?) sticks in my mind
I also like several beers of the Porter variety, I even had a Porter in San Francisco brewed by the Thirsty Bear brewing company, very nice, malty and chocolatey
The problem with anything like this is that the occasion and the taste become mixed up and a memorable gig, pub or outside setting can affect your memory of a beer. I have fond memories of Damm Estrella in Barcelona, sitting in Parc Guell overlooking the whole of the city. Now I know that the beer is fine, but somehow less than the nectar I taste in my memory (it was my honeymoon).
Another problem especially here in the UK is cask-conditioned beers. This means that any given ale on any given day in any given pub can be anything from perfect to drain cleaner. Don't get me wrong, cask is better than keg but it can lead to major disappointments if the landlord or cellerman does not know what they are doing. This leads to surprises the other way. While at university I had to go to the Post Office depot to pick up a parcel, but when I got there the van hadn't returned and could we come back later. The depot was out in the middle of a major industrial park and it looked like there was nothing to do. Then I spotted a working mans club and went inside for a beer - it was a warm day and I'd walked 2-3 miles. The beer was Tetleys, a standard bitter beer from Leeds, well known to me as just that, a standard beer. Well, as you can already tell as I'm telling this story nearly 20 years later, the beer was a revelation. If I could reproduce just one pint it would be that one. (although any of the next 6 would also work). It was the combination of a fine conditioned beer looked after by the cellerman.
One final thing - fruit beers - euurggghhh.