I guess you just need to work out what you can do yourself and what it is worth paying someone else to do. I try and distinguish being "paying for expertise" and "paying for time". I've made a point of learning to do oil changes myself as that is just time. I personally don't feel comfortable touching the trans at the moment, as too much/too little oil can do funny things in auto.
Personally I would do oil + upper engine + cabin filter myself. If you do coolant yourself, it's a bitch to dispose of legally from memory (there is another thread on here about that). Brakes/coolant/trans are out of my current comfort zone but at the very least brakes and diff are things I plan on learning to do eventually.
And RE cabin filters, it also depends on whether it is an activated carbon one or not. If it is, they are expensive, if it isn't, $70 is way to much.