Money is nice but spent all too quickly - there is no lasting reminder of any effort you put forward.
Once I was asked to led a 3-week crash effort for EDS to salvage the GM Credit Card processing from buckling under load. It had the highest corporate visibility possible. We completed round the clock efforts late Thanksgiving evening to migrate to faster hardware and completely re-architect the CICS regions used for Credit Authorizations. The site was out of state so I missed Thanksgiving with my family. We waited and hoped. On "Black Friday", the account surpassed all prior numbers for authorizations processed and all within SLA's. An understatement - EVERYONE was happy.
As a reward I was offered a weekend at the beach with my family, or a gift. I wanted something tangible, so I choose a nice patio table and chairs set for our new house. Almost 20 years later, the set is still in use on the porch. Last weekend as we used it again, it recalls to me and the family the personal sacrifice, and to me the personal satisfaction of hard, skillful work well done, and the happy memories of the time, the events, and the team.
Money would be long gone and forgotten, or another beach trip would now be a far fading memory if recalled at all.
Every day though, I have and can use a lasting reward for effort and a tangible "thanks!" from my employer.