This is an interesting post and I look forward to reading the various responses!
My current dream is simply to have enough songs published and periodically placed to provide a modest but consistant income stream to support the occasional acquisition of new gear (I rarely buy gear unless it will pay for itself).
My view is likely different than many since I'm looking at the tail end of my "career". I've seen many sides of the music industry, having toured, recorded, etc. etc. I have a rather jaded view of the state of the industry and much lowered expections than I once did. That being said - I think it is very important that young artists do have dreams and more importantly, have a plan to achieve those dreams.
In my teens I simply wanted to gig and travel without a long term view. As I entered my twenties I established a goal of a specific level of regional success (consistant regional tours with "label support", etc.). I commited that If I did not achieve certain "benchmarks" by the age of 25 - I would no longer pursue music on a full time basis. I did work "full time" for 7 years but never at a level that I felt would support a long term, decent life style.
In my 30's I simply wanted to gig on a local level as much as possile while holding down a decent day gig - with an increased focus on being a "session musician" for various local studios. I felt it was important to be a steady "working musician" and while I gigged and/or recorded a lot (often as much as 6 nights per week) I often took gigs with musicians who were not at the high level I considered myself - but they paid well. While I called, myself the ultimate "sideman" I actually considered myself a musical slut.
In my 40's I became more selective about the gigs I accepted or more importantly the musicians I chose to work with. While my music income was less, my satisfaction increased and I was no longer a musical slut. I started to focus much more on songwriting/composing and started to spend any music income into improving my studio/recording gear.
Now in my 50's I find gigging to be less fun (coming home at 3:00am stinking of stale cigarette smoke and then going to work on 3 hours sleep don't seem as "cool" as it once did

) and studio work is now much harder to come by - so songwriting has become a primary focus (writing and recording). I've had some minor "success", with each year seeing a little more income than the year before - which brings me back to my current dream.