Joined: Jan 2009
Posts: 44,240
Likes: 6,494
From: New York, NY, and High Falls, NY, USA
Bikes: 1962 Rudge Sports, 1971 Raleigh Super Course, 1971 Raleigh Pro Track, 1974 Raleigh International, 1975 Viscount Fixie, 1982 McLean, 1996 Lemond (Ti), 2002 Burley Zydeco tandem
I fear you want to upgrade for the joy of ownership, not for functional reasons. If so, at least be honest.
The biggest bang for the buck in upgrading is not in wheels but in tires.
Pedals won't make a darn bit of difference unless (1) your current pedals are uncomfortable or (2) you want to change your foot attachment system, such as by getting clipless pedals.
You can upgrade your brakes with Kool Stop brake shoes. Not as sexy as new calipers, but they may make all the difference you need. And it's a low-risk experiment, at $10 per pair.
Save your money for a new bike, and consider the advantage of having two bikes: one for transport and one for pleasure rides. You'll get stoked to ride your "nice" bike on pleasure rides, and you'll let your old bike be what it is and appreciate it for what it is. And if something should happen to it, like a calamity or theft, you won't be too crushed.