I would like to get a punch set, but I'm overwhelmed by the amount of dissent sizes and types available.  I know the difference between roll pin punches and regular pin punches, but where do "starter punches" fit in there in terms of purpose and physical differences?  What size of each punch would I need to break everything down and put it all back together?  

I was looking at an 11 piece Cornwell roll pin punch set when the truck was at work yesterday, but I'drather just buy exactly what I need individually rather than have a bunch of extra punches I don't need.  I have a S&W M&P15 Sport if that makes a difference.

What size roll pin punches, standard pin punches, and starter punches will I need for any foreseeable maintenance?  

Edit: Should the punches be steel, or brass to prevent damage to parts?  I'm not even sure if they make brass punches this small since it's so soft, but as you can tell I'm a noob when it comes to punches so I'm open to opinions.  Thanks!

For maintenance?  None

I mean for complete disassembly and reassembly of all pins, detents, etc.

Would that set be better than the Grace 8-pc brass roll pin punch set?  Are brass punches too soft to be reliable or are they just as useful while being safer?

Get some from Sears. When you break them, they'll replace them.

I just use a Dasco Punch set.
http://www.amazon.com/Dasco-88-Punch-Chisel-12-Piece/dp/B00FOOD1GC/ref=sr_1_2?ie=UTF8&qid=1417148989&sr=8-2&keywords=dasco+punch+set

This.

And for regular steel punches.................This

One person's opinion:  I just assembled my first lower, and in the process I bent a Grace 3/32" brass roll pin punch pretty badly.  That Grace steel punch set looks quite attractive right now.

What's the opinion on using roll pin holders, like these from Brownells? I used the tape-and-pliers method to hold the pin in place, but that was awkward, even with the lower in a vice block.

EDIT:  Ok, after reading the third post in this thread I found out I was doing the tape-and-pliers method wrong.  Don't ask.

None, buy ammo.

You have no reason to ever punch out any pins for maintenance purposes.  Ever.

Maintenance may have been the wrong term.  As I said before, I just wanted to know what size punches I'd need to remove and install every pin in the firearm (for replacing parts, for example).  Another example, I'm getting an H3 buffer in the mail soon so I can use the 3 tungsten weights to create a H/H2 buffer with my Carbine buffer, and I'll need to punch the roll pins out to swap weights.  That kind of thing.

Starrett is my go to brand. 1/8" and 1/16" is probably all you need.

Starter sets are a bit larger but have a hole in them to hold your roll pin. Use these to get your pins started and finish them with the standard punches.

Don't know about the rest of the people here but I bend and break these things all the time.  Don't spend a bunch of money on them.

There are holder/starter punches for roll pins that have a hole in the end of the punch to retain the roll pin when starting it into the hole.
A starter punch will be very short which makes it easier to drive roll pins that are tight without bending the punch.
Definitely steel for driving roll pins.
Straight punches are used for solid pins.
Brass punches have their uses, but I can’t really remember when I last used one on an AR.