Shwagon, you say DIY. Are you thinking about doing it yourself?
If so, your first choice is going to be a new construction window, or a replacement window. Specifically, a replacement window fits within your old frame, while a replacement window requires ripping everything out down to the studs, and reinstalling.
In my case, the wooden frame, sill, and exterior brickmould wasn't in great shape, so I opted for new construction windows. They are also cheaper, but the installation is a lot more.
I've been doing them myself, and have done 2 so far. I'm done. I had the installer for a local Anderson dealer offer me $350 a window for the labor. I'm spending enough time per window that it's worth it to me. The main reason why is that my construction is concrete block, so I've been building and tapconning pressure treated buck frames. I've also needed to trim the studs a little to get the standard sizes to fit (my studs aren't load-bearing, since the walls are concrete block, they basically serve as furring strips to nail drywall to).
In a normal house, with, say, 2x6 walls and Tyvek, I think I could do a new construction window in a day by myself.