I needed/wanted a second VHF/UHF antenna and chose a Discone. Why? Simple: Wide band recieve and transmit. They don't have any gain, but they are still very handy.
I picked the Diamond D3000N Discone. It has a recieve range of 25Mhz to 3Ghz. It has a wide transmit range covering the 144Mhz, 222Mhz, 440Mhz, 900Mhz, and 1.2Ghz amateur bands at a Max Power of 200 watts. It can also transmit on 50Mhz with a max power of 20 watts FM, 50 watts PEP.
Here's a picture from Diamond's website:
I have two chimneys on my house, which you can see in the pictures of the X300 2m/70cm antenna. I installed the discone on the other chimney. As you can see I didn't need a lift to install this antenna! A buddy of mine who doens't mind roofs as much as I do was drafted for the job.
Depsite not having any gain, this antenna has exceeded my exectations on what it can do for transmit. I'm currently using it for 220mhz and for my scanner. I'm very pleased!