Pork and earmarks have existed since the beginning of time. Without pork, nothing controversial would ever get through congress, sad to say. I sounds so simple to eliminate, but its rather impractical to ever get passed.
Yes, you can't have any real budget cuts without going after defense, social security and medicare. Given that medicare is nothing but a very basic safety net, there is little you can do there except continue to clean-up system fraud and improve delivery, both which take some capital investment (which is a short-term adverse affect on budgets). Social security can only be attacked from the standpoint of adjusting eligibility ages as we are not exactly enriching our seniors with benefits. Its just basic, and the only thing standing between poverty and some degree of self-sustainability for 65% of our seniors. Instead, we have to encourage our workers to work to 70 or 75 but broaden disability. That is a tough sell to the baby-boomer population that thinks they are nearing the finish line. Defense is the 3rd rail.... though we spend more on defense than all of the other nations in the world put together, its just politically impossible to go very far here. All in, there are not deep, deep cuts to be had anywhere.
My favorite budget cut would be to cut congressional pay and benefits. These guys waste more time in their political wrangling, committee investigations, fact-finding trips, legislative obstructionism, campaigning on government funds.... the job should become less desirable. For our strict constitutionalist friends, our founding fathers did not advocate for a ruling class where members served for life, but rather for a government of the citizenry where members served.