Looks like you have received quite a few responses to your post. Don, KB9UMT, provides some great web sites for you to check out.
I too have built my own antennas for ten meters. Running 25 watts USB.
1. Horizontal Dipole in third floor of my house. This was a test antenna, just to see how it performs. Consistantly made contacts with the east coast and west. However, due to orintation, no contacts made south or north of my location.
2. Sloper Dipole up 40' (Slopes to the south 45 degrees and this is the same dipole used in #1). Works great! Consistant coverage into the South Pacific, South America, East Coast and West Coast of North America. This one is a keeper.
3. Half-Wave Vertical mounted on the ground. I made a 1/2 wave dipole, and hung it vertically from a tree branch. Noisier than #2 and the received signals are not nearly as strong as from #2. However, I am making contacts with it. Not real happy with it so I am going to modify it...see #4.
4. Half-Wave Vertical with counterpoise. This the antenna found in #3 with 1/4 wave ground wires tied together to form a circular ground plande directly under the antenna. Under construction. Go here: http://www.karlquist.com/ground.pdf
to read an article about such an antenna.
Good luck, have fun and 73!