No need to replace any parts that work. It sounds like the bike's been sitting and you haven't been into the sport for a good while. If that's the case and you don't already have them, good gift ideas would be:
1) A bike stand (doesn't have to be fancy - can be <$100 with a little shopping)
2) A good basic set of bike tools (chain tool, cassette tool, cable cutters, crank puller, pedal wrench) and any basic tools you don't have that also work on bikes (socket set, needle nose pliers, metric allen wrench set, etc).
3) A copy of Zinn and the Art of Mountain Bike Maintenance
This way, you can clean and inspect the bike properly and repair any problems. What needs to be done depends how much mileage you put on the bike before and how it was stored, but you'll definitely want to remove, clean, inspect and relube (as appropriate) all major components if you're putting it back in regular service. You don't want surprises on the trail...
Of course the tools and book will come in handy for your new ride next year, too.