Oh man.. whichever route you go, be careful you don't end up doing what I did this year..
I started PM on the stove (2004 couple hundred bucks in equipment), then went AG on the stove (2008 couple hundred bucks in equipment), then bought four kegs, a regulator, lines etc. to handle three kegs on pressure and serving (2011 again, a couple hundred bucks) but never kegged anything due to my transient nature (moved from VT->NYC->CT in a short period).
Well this year I decided I wanted to actually keg (since I have a secondary fridge), and be able to handle commercial kegs; so I bought a bunch of crap, and my wife freaked out about me taking over the second fridge, so now I'm buying a chest freezer, while I'm doing that I'm increasing my on tap offering ability to 6, even though I only have four kegs right now (since I'll have the room in the keezer anyways right?) and picking up a larger CO2 tank.
in 2014 I'm going to begin my 10 gallon E-HERMS build in the basement (Arguably RIMS in this stage), which let me tell you, isn't going to be cheap - one 80qt pot, 70 qt cooler, one pump, counterflow chiller, PID controller, not to mention the added breaker and wiring & element. On top of that pick up more kegs.
either in late 2014 or early 2015 I'll finish the E-HERMS build by adding in another 80qt pot and another pump, another element, probably pick up more kegs, not to have more on tap but to have more in backlog.
This year alone I've spent $750 so far between equipment and ingredients and I'm a cheap SOB; I'm still not done yet.
I think my words of advice are; think out where you want to be then buy stuff.
Are you going to jump from 5 gal outside batches to 10 gal outdoor batches in the future? are you going to want to go from outside brewing to inside brewing? <-- that is the exact reason I'm sticking with my AG stovetop setup and building my 10 gal E-HERMS setup in the basement.
The arguments against kegging aren't as strong - you will essentially use that equipment until you stop brewing, where as stock pots are only good as long as you are brewing that size batch.
I can currently do 6 gal AG on the stove or 12 gal PM on the stove, although I'm thinking of picking up an 1800 watt induction cooktop to make AG on the stove easier, and possibly jump me to 12gal AG on the stove; see there I go again...
Just some food for thought; hope that helps a bit...