Well, I used to list a lot, but it's getting so complicated now that some sorting out is needed, so I am reducing this to general notes. It should be noted that these are my opinion – you may well find differently.
I prefer real ale, though that is not a fixed rule. In fact my order of preference is cask, bottle conditioned, can conditioned, keykeg conditioned, keg, brewery conditioned bottle, brewery conditioned can. The first four count as real ale, the other three as processed.
If I can get it, I tend to drink dark mild. There are subtle differences between different brands, but mostly, they are very similar. South Staffordshire, the West Riding of Yorkshire and Suffolk in particular produce good mild. There are only three I have tried so far that I did not like – Kimberley, not that I found much good Nottinghamshire beer anyway, Bateman's DM, and Adnams, but they do make another mild which is good.
Pale mild is rare, but is my next preference, unless it is cheaper than dark mild. I have only ever tried three brands, as production of most of the others ended in the 1980s, and one of the three was more like bitter in my opinion.
Of course, bitter is common – it can be obtained all over the place. East Staffordshire, the West Riding of Yorkshire, Suffolk, Lancashire and Essex are the main areas producing the best, but there are plenty of quite acceptable examples from elsewhere. However, the worst examples seem to come from Nottinghamshire, and one particularly bad one from Oxfordshire – Morrell's – but then again, few of the pubs kept a good supply of it as everyone used to drink their draught Light instead. Sadly, production of that ended in 1991, but I did get a chance to try it before it utterly disappeared. In a Morrell's pub these days, I will tend to drink Varsity, unless there is a notable guest I'd prefer.
I am now finding much to like about golden ale – it has grown on me from initially appearing tart. Good IPA goes down well too.
In Scotland, things are very different indeed – the traditional Scottish Light, Heavy and Export are very interesting and on the whole rather good. I have never yet tried a Wee Heavy.
Of course, I don't mind beer from outside the UK – much of it is effectively lager which is fine, as far as it goes, but there is much else to find interesting, including Belgian Ale. In France, there are a number of amber and brown beers that are similar in taste to bitter and mild respectively. One brewery even makes one it describes as English-style.
If you're ever close enough to buy me beer, you know which kinds I like now.