For a light weight two person capability we use a Sierra Designs Clip 2 CD Tent. It works very well as far as keeping us dry, and is light enough. It is a three season tent. We cannot bring our equipment indoors though. When I travel by myself, it works much better in that respect. We should have purchased a Clip 3, then we would have more room for us and our equipment.
http://store.yahoo.com/msoutdoor/sierdesclip3.html
For SAG tours (when we have equipment sagged) we have gone to a much larger tent.....5 person! It's an Eddie Bauer setup that we purchased at Target! With the cover off it is almost a full screened cover. With the cover over the top it is rain proof, and has kept us dry so far. With this tent we can put a double air mattress, all of our gear and our tandem inside of it and have room left over to stretch our legs! It looks something like on the site below:
http://www.target.com/common/catalog...ush&navCount=7