Are you just drinking or having it with a meal?
You've not lived till you've had a champagne blow job.
I'll go with that. I've only had one, but by God, it was good!
If you don't know much about wines, there are a few hints and tips that can help without going into technical details.
1) If there aren't many bottles of a particular type left on the shelf, chances are it's popular and drinkable. (Not always a guarantee as it could be on special offer or they may be running out.)
2) Choose a wine with a fairly plain label. They tend to be better. The wine sells itself without having to go, "Wahey! Look at me!"
3) Read the label. That will tell you how sweet, dry or robust etc and give you an idea of what to drink it with.
4) High alcohol content doesn't always mean a good wine.
5) Expensive doesn't always mean good wine either.
6) Just because you've had one bad bottle doesn't mean that every one of that type is nasty. You could have just been unlucky.
Try a few different ones. Keep a list of ones you've liked and ones you've hated. It makes it easier next time.
If you're in an off licence/bottle shop, whatever talk to the staff. They can give you advice and point you in the right direction.