The midrange is part of the component set, and having just a midrange driver does you no good at all. And they are all "regular" speakers.
Midrange drivers play the midrange frequencies (~250hz - 4500hz or so).
A component set consists of a tweeter and a midwoofer (a driver that playes the midbass and midrange). Or, in a 3-way component set you have a tweeter, a midrange and a midbass.
You don't want just a midrange speaker without something to play the higher frequencies (tweeter) and lower frequencies (midbass). And you can't have a component set without including a "mid" in that set.
What is a "regular" speaker? They are all "regular" speakers.
The component set should include everything you need depending on the set, but it should cover most major frequency variations. Also, it would be a shame to run a new comp set off of a HU, so you should consider buying an amplifier for them.
wouldn't be a bad choice. A few people will come in here and say get the phoenix gold component set off ebay that sells for about that much. I've never heard said component set, so I can't advise either.