A GM doesn’t have to constantly reward his players with gold and magic items. Providing other types of rewards keeps things fresh and interesting while building the verisimilitude and depth of the campaign world.
Favours: Having a person owe you a favour can be very rewarding. Of course, the “power” of the favour depends on who owes it, but even the humblest peasant can provide neophyte adventurers with shelter, local knowledge and so on. Noblemen, powerful clergy and archmages can offer truly unique, priceless assistance to people to whom they owe a favour.
Information: Information is power. Having the right kind of information to bypass a deadly trap, slay a particular foe or to even find the dungeon is often the difference between glorious success and bloody failure. That’s well worth a few piece of gold!
Items: In games in which the PCs cannot simply buy whatever magic items they desire having a NPC gift or craft them the item(s) of their dreams is a huge favour. The PC may even be able to make the item slightly different to normal examples of such items perhaps by customising its appearance or slightly tweaking its abilities.
Property: Rundown buildings, small businesses and suchlike can make great rewards. They provide something for the PCs to do outside adventuring and can act as springboards to future adventures.
Renown: Success breeds fame and fame is often a handy thing to have. The PCs may receive preferential treatment in towns, the mention of their names may reduce many of their enemies to quaking cowards and so on. (Of course, this can also work against them as various shadowy cults, evil villains and suchlike can learn about them by listening to the stories of their heroics.)
Spellcasting: Sometimes the party doesn’t have access to all the spells it needs – perhaps the classic example is raise dead. Often, such spells have valuable or rare material components the party may also not possess. In this situation, having an NPC cast these spells for you is a terrific reward.
Story Progression: As well as clearing the dungeon and slaying its master, in a campaign with an over arcing plot the PCs can gain the information required to continue to the next adventure. Alternatively, the PCs could gain information that provides them with a substantial advantage. Gaining such information can provide the players with an amazing sense of achievement.
Titles: Some titles are meaningless while others may come with land and property. All have responsibilities and elevate the holder above the great unwashed masses.