Ex isn't horrid, and if it's available I might get it. MGD is putrid, I'm not sure I've ever had Sam Adams (nor would I want to...). For drinking at home, I drink either Laker Red (I like it more than Rickard's Red and it's about as cheap a beer as you can get) or Beau's Lugtread (my absolute favourite beer, but with the amount I drink, it's more of a treat than an every day beer...)
The only Mexican beer (at least the only one I've ever had) that doesn't suck hard is Dos Equis. Corona and Sol are f***ing gross.