thats going to depend on what exactly you want done. Whether or not your going bigger or stock bore. how bad the block is, if its cracked or what. we need some more info.
I am in the same boat. I have found though, if you are going to put good internals (read forged pistons, etc) in the block sometimes it is cheaper to just buy the short block. WIth the stroker setup I am considering, by the time I get the block worked, and buy the internals, I am only ~$300 shy of the cost of a shortblock, this is without balancing the rotating assembly (~$200)and for me, I don't make my living putting motors together, so I will find a reputable company that does and let them do it for me and save a little more and spend a little more for a better finished product.
There are several approaches here. If you need the car up and running, the best approach is to find a core motor and rebuild it, then just swap it in.
For a basic rebuild of the stock 5.0, doing it a home, with only the machine work farmed out, you could probably do it for $900 to 1300 at the least. Cleaning, inspection and machine work, for the block and heads will be $4-700 or so, parts are the rest. Rock bottom would be finding that you can just rering, and not have to buy new, oversize pistons.
If you go to upgrading stuff, think in the $2000 to $3500 range, easily.
You really don't need a lot of high dollar parts for a street car, the stock type stuff will go a long way.
Obviously, the longblock route is fast.
The most street performance will be from a basicly stock short block with as much money as possible put towards better heads or porting, etc.