Drawing for outs on the flop?

As I have been moving up and away from stict nut peddling, I have run into (or been faced with) numerous situations where I'm not sure what the best play on such flops are.

Basically, all the situations involve drawing for outs (not necessarily made hand) on the flop.

For example:

You hold A[img]/images/graemlins/diamond.gif[/img] Q[img]/images/graemlins/diamond.gif[/img] 10[img]/images/graemlins/spade.gif[/img] 7[img]/images/graemlins/spade.gif[/img] in the CO.

In an unraised pot, 4 see the flop of J[img]/images/graemlins/diamond.gif[/img] 8[img]/images/graemlins/spade.gif[/img] 5[img]/images/graemlins/heart.gif[/img]

Play has been pretty passive pre-flop and aggro post-flop at the table. EP1 checks, EP2 leads for the pot, MP folds and it is to you. Assume roughly equal 100BB stacks.

What is your play on the flop? Take a card off or muck and move on?

How much does your thinking change if you are EP2 with the same holding and an aggressive CO (last to act) pots it?