I mostly back pack. Here's what I've got:

-Winter, 1 or 2 person - An old North Face tent that I bought used in the late 80's. I'm pretty sure it's from the 70's. I have no idea what model it is, but it's fairly light for a four season tent at about 7.5 lbs. I've taken it through some pretty good storms (in terms of wind velocity), but I've never taken it through a big dump of heavy, wet snow.

-Three season, 2 person - Big Agnes Sunnyslope 2. Big Agnes has a pretty good reputation in the backpacking community. I have to say my tent has lived up to the Big Agnes reputation. I went through a major, sustained thunderstorm in the Rockies, and not one drop got inside. The rain from the thunderstorm was coming down so hard that there were splash marks almost all the way to the top of the tent, and the Sunnyslope 2 is not a low-slung tent.

-Summer, 1 person - Hennesy Hammock. A very comfortable, practical shelter if you're in areas with trees and not a lot of brush and the weather's good. I've frozen my butt off in the fall. I only take the hammock if I'm familiar with the place I intend to camp. In S. Calif, one cannot always count on suitable trees.

-Summer, 1 person - OR Aurora bivy. For when I don't know that I can use my hammock. Very light and compact, but like most bivvies, a bit claustrophobic. I get the sense too that the bivvy compresses my down bag a bit. I've been cold even at temperatures well above the rating of my sleeping bag when using the bivvy whereas I sleep much more warmly in a tent.

Also for summer, I have a 1 person Kelty Dart I. If you're looking for a one person shelter, don't get this one. I've found it has huge condensation problems and is a bit small for a six footer like me.

For car camping, I have a Sierra Designs Omega tent which is a spacious backpacking tent. My (petite) wife and I fit inside with room to spare. My Omega is a bit more comfortable with it's extra space and multiple pockets, but is heavier than my Sunnyslope 2 which is why I tend to use the Omega for car camping.

Lastly, I've got an REI Camp Dome 2 that I picked up at a Used Gear Sale for something like $25.00. It's a bit small for me (short mainly). I use the tent as a loaner for friends who want to camp or backpack but don't have all their own gear (or don't want to take their good gear on a plane when they visit from out of town). For $25.00, it's no big loss if "stuff happens."