I guess electronic hobbies are becoming obsolete. Radio Shack and Heathkit were my two favorite sources. Many a weekend I was up overnight(s) soldering and assembling projects and enjoying it to the max. It seemed like "soldering adrenaline" was much more powerful than the caffeine in coffee.
Now it's hard to find kits anymore.
I always loved the smell of solder... but then again Testors plastic model cement also had a sweet smell...
There are still some fantastic kit manufacturers out there, though most specialize in ham radio gear rather than general electronics. Give these a try:
Elecraft
Small Wonder Labs
Oak Hills Research
Emtech
Milestone Technologies
Ramsey Electronics
Ten-Tec Kits
Wilderness Radio
Kitbuilding is still alive and well!