+1 to those who say it's worth replacing the tires if you'll be riding it a lot.

Another thing that's relevant this time of year: if you're going to keep the old tires/tubes, keep in mind that changes in temperature can affect pressure fairly dramatically. I've seen old tires that seemed just fine, when fully inflated in a cool basement, literally explode when the bike was parked after a ride on hot summer asphalt.