If the frame, bottom bracket and wheels are in good nick, bin the rest and refurb. Don't just walk into a bike shop and say "Suntour/Shimano/Campagnolo! Oh Shiny!" Research first. Get a complete set of brakes, gears, chainset, shifters and levers only if it makes sense. There is no use being a complete label whore, I should know, I used to be one, 8-)
If your wheels are stuffed, get hand-built ones if you can afford them. If not, get the best pre-built ones you can afford with your budget and get your bike shop to true them.
And make sure you can trust the bike mechanic if you are not doing the job yourself.