*Damn it, mixed up my letters!*
When players are divvying up their rewards, they expect a few things: cash money, new and exciting equipment, and perhaps the odd bit of magic. One thing I find (which can really add depth to a campaign) is to give some less tangible (but no less useful) rewards, just to mix things up.
Say you've been hired to clear out a Kobold warren by the King's advisor - many players would expect a dip from the King's funds to supplement their own wealth. But, it can get stale - too little, and it's not worth the hassle, too much, and suddenly the players are rolling about in cash they can't spend (and it can stretch disbelief that the King would hire adventurers at 500gp each, when that money could train and outfit a small group of guards to do the job).
So, instead, offer the players a Favour. It can be used at any point within reason - so, should they require a small battalion, the King might send a few well-trained men, or a larger number of lesser warriors, to help the party. Or perhaps the King's Mage will cast a spell for them, at some point, or they might get let off with a small offence (like causing a barfight, or getting into other small scrapes that would call for prison time). These sorts of Favours can be a lot handier than a +1 sword, and help immerse characters in the world they inhabit.
Or, for greater deeds, they might be granted Prestige. Prestige includes titles, lands, and positions of power and influence. Old-school D&D had these as part of the advancement scheme, with the building of fortresses, guilds and Towers. But, in newer games, it's all about the money and items - let's try and bring that back a bit.
Yes, being gifted a +5 Holy Avenger for services to your temple is pretty cool, but picture being granted the title of Chapter Master - you have control over a whole squad of Paladins (of lower level than yourself, of course). Yes, you might need to stop in and do some paperwork, but most smart players will hire a replacement or a secretary to handle the real paperwork while they are out adventuring.
Some are easier than others to maintain - while the Chapter Master has quite a few rules to follow, and work to do, being granted an honorary position in the College of Magic would have a lot of benefits - as well as the possibility of getting paid to go adventuring with your students in tow! Just call it a "field trip", and try and not kill too many of them, and you're off!
In my current Rogue Trader campaign, the player found an ancient starship - and decided to return it to the Adeptus Mechanicus, like a good God-Emperor-fearing Imperial citizen. As I simply couldn't fathom what type of monetary reward to grant her (money is such a non-issue in RT, there's a stat to determine how rich you are), I decided instead to have the AdMech hold a small parade in her honour, spreading word of her actions across the Expanse, and finally, grant her honorary Tech-Priest status - a practically a unique title. Thus, she unlocked a lot of interesting elements of the setting, as well as a guarantee that the AdMech would help take care of her.
Of course, she could still lose this privilege - it now gives her some extra rules and responsibilities. But, I can tie those back into the game, making it seem deeper, more real, and of course, more fun.
And that's what these sort of rewards do, when you do them right - add fun.