In my experience I have come across two forms of "resets" on daily quests and rewards; the "Server side" and the "Player side". When I say server side I mean the reset is tied to the server, as in it happens at a specific time of day for everyone. For example, in Guild Wars 2 all dailies and such reset at exactly 5 PM PST. For player side, it is when the reset is tied to the account of the player. An example of this is League of Legends, where the first win of the day bonus returns something like 22 hours after it is completed. Both have their strengths and benefits, and I find I am troubled in figuring out which I like more.
With the server side comes predictability and uniformity; which can be problematic and beneficial. It has the plus side of allowing me to plan my play around the reset without any extra math in my head; I just know that when I get home from work I am fairly sure to have a fresh set of dailies to do. On the other hand, it also means that everyone else is doing to be doing the dailies at the same time, which can be somewhat troublesome in a game like Guild Wars 2 where everyone has the same ones. In Firefall the reset seems to be late at night PST, so it is more of a "day" thing for me. Either way, it allows a level of clear predictability and consistency.
On the other hand, the player reset does too, but in a different way. I recall the early days of calculating out when my WoW dailies would reset so I would know exactly when to start. The thing is, these days I don't want to bother marking my calendar to know, so I just stopped caring and the daily in a game like League of Legends comes as a random bonus. In theory it allows you to also "push" your reset to be earlier, since most games have the reset actually be 21-22 hours instead of 24 (a wise choice in my opinion). This method alleviates the problem of having a horde of players trying to finish the same daily at once, but also adds that element of uncertainty for me.
Still, I am finding I think I prefer the predictable "at X time" resets because it allows a level of certainty and consistency; it's something I don't have to think about. Which do you prefer?