Choosing a new external drive

Ok, I am looking to get a replacement external drive. I currently have a RPI 2 with a 5.25v power adapter. I am running a wifi adapter, wireless KB/mouse, and tv tuner off the usb ports.
Will I be able to use a normal external drive that is not externally powered, or should I look for a powered one?

Pi’s have enough power issues as it is. It’s best to get a hard drive with it’s own power supply.

Yeah, kind of what I thought. I had enough issues getting it to have 5v stable as it is.