Kinda hard to answer that question without knowing what you already have...but I think you're on the right track by starting with a focus on yourself. Get out there and run, get strong, lose weight...spending lots of money to shave 5 pounds off your pack won't matter so much if you're really fit.
I used to be pretty into racing road bicycles...I'd see this all the time; someone gets the idea that a $2000 wheelset will make them faster when they could be training so much smarter for much better returns....
I almost got caught up in this with the 40% off frenzy at backcountry.com...I was about to lay down $135 to get a GoLite quilt to shave 8 oz. off my current, perfectly good bag.
What's 8 oz.? I figure I'll try and commit to stepping up my running mileage instead. 3 months from now it'll pay a much greater return than 8 oz.
As for free ways to lighten your pack, start with a look at each item in your kit and ask yourself the following:
1. When, if ever, was the last time I used it? If you're not sure, dump it.
2. Is there something else in my pack that serves the same purpose? If so, take the better/lighter one. Don't carry a bunch of spare stuff.
3. An UL kitchen is really easy/cheap/almost free to make. Go get a Heineken can for a pot, make a cat can stove, get some esbit tabs, etc. Dump lids and use foil.
4. Look at other people's gear lists.
5. Go buy cheap alternatives! You don't have to have a super-duper spinnaker tarp to go camp- go buy a plastic tarp and get out there...