"Condenser or USB" isn't really a question.
"Condenser or Dynamic" is a question, and the answer depends on "What am I doing with it, and what else do I have in my arsenal?" Then you get to answer "How am I going to hook this sucker up to my computing box?"
If you are going to be recording in your house and going to be recording a variety of instruments, I'd always opt for a condenser over a dynamic mic. Condensers are much more sensitive to input so you'll get better fidelity in your recording. The frequency response for condensers is a whole lot flatter than for dynamics, which tend to lose considerable signal on the low end. If I'm going to be recording high volume signals like a guitar amplifier, or taking it on the road for use on stage, I'd opt for a dynamic microphone. Durability, resistance to feedback, and the ability to handle high spl is what you will get with a dynamic mic.
The USB vs XLR (or 1/4 inch plug) question depends on whether you have an audio interface capable of handling microphones or not. If you have no other equipment go with a USB mic it will do your D-A conversion for you, and you can basically plug it in and go. If you have an external interface, I wouldn't go with the USB. One of the nice things about an external interface is that you can upgrade it to get better pre-amps and DACs while with a USB mic, you're stuck with what is in the mic. Nothing other than a new mic will fix that. And remember, most condenser mics require a +48v "phantom power" signal in order to work. A USB condenser will usually provide that on it's own, but an externally connected mic will need that through the pre-amp to which it is connected.