First brew the best possible beer that can be brewed (AG), then worry about how to store/dispense.
+1 on this...
I actually did it the other way, only because I got a FANTASTIC deal on two cornies, a tank and a regulator. In the long run, it still was not a good enough deal. All it means is that I have had convenient inferior beer. What I want is awesome beer, no matter what it is being poured out of, and the first step toward that for you is a full size kettle, so that you can do full boil. You will get less kettle carmelization of the wort, giving you lighter color and truer flavors to your beer. You will also get better hop utilization, also improving the quality of your beer.
Last but not least, here is the big kicker for me, if you are going to be brewing no matter what, then going all grain, and then getting a mill and milling the grain yourself, will pay for itself, and then for your kegging system fairly quickly.
With better hop utilization, you will need less of them for the same flavor in your beer. There is your first money savings per batch. Not a huge savings, mind you, but it all adds up.
Next is the switch from extract to grain. My LHBS charges $1.25 per pound for base malt, and $2 per pound for bulk LME. Lets say for a roughly 1.050 OG pale ale, you need roughly 9# of base malt ($11 from my LHBS), you would need roughly 7# of LME ($14 from my LHBS). There is your second savings per batch.
Last, by milling my own grain, my cost from the LHBS goes from $1.25 per pound to only about $0.6 per pound, and on top of that, I get about a 10% increase in efficiency over the milling that the LHBS does, so it is half the cost, and I need less. Now that 9# of base malt is only about 8#, and it costs me about $5.
So, by having the right tools for full boil AG brewing, I just saved over $9 per 5 gallon batch. There are a number of mills out there for less than $100, so even if you are brewing 5 gallons a month, you pay for that in less than a year. Brew more than once a month, and you will start paying for that kegging system pretty quick too.
