Job satisfaction is a funny thing - while there is a definite relationship between the benefits you receive for a job well done and the resultant satisfaction, the correlation only extends so far - and at the higher levels of expectation and remuneration, there can even be a detrimental effect on the appeal of a particular position.
The Bottom End
For those in an entry level position, or those who deem themselves to be beneath the market average for a given role, the lack of financial reward may hamper the resultant sense of satisfaction and self worth. Being underpaid for work that others may do for considerably more is a considerable downer for morale, and can be a cause for a worker to look elsewhere for employment.
As you'd expect, then - as salary increases for a given position the general level of satisfaction will increase in a correlating fashion - but at a point around the market average things will start to change, as payment beyond market rates usually requires a greater commitment.
The Perils of Middle Management
For the technical worker who wishes to progress up the ranks and beyond the core positions in the middle, there is ample opportunity. One such way is to take on more responsibilities, in either a project scope sense or in a managerial one.
Such endeavour to escalate one's career can lead to dangers as far as happiness is concerned - while increased responsibility may be beneficial to some, in most cases such a path will lead to an increased workload and a resultant rise in stress levels. This is, of course, not always the case - in some cases such promotions will grant more flexibility in a role, more creative control.
Achieving Nirvana
The perfect blend between reward and enjoyment is difficult to attain; there are very few jobs that both pay exceedingly well and provide a fulfilling, stress-free existence. The fortunate few who are in this position are probably toting highly specific and sought-after skill sets - particularly within leading edge and high-tech companies.
While we can't all aspire to such heights, that's not to say that you can't forge an enjoyable niche beyond the level of the average. While it may be sometimes impossible to avoid the cloying nature of elevating responsibility during your career, the worker who values job satisfaction over monetary concerns may find a sweet spot between the two.