I'm a huge theory geek, so I'm gonna go on a bit of a rant about counterpoint. Hopefully this will make sense to someone. Yes, I-IV-V-I works. But why does it work? Because it follow counterpoint! When writing a progression in a major key, this is how Mozart did it. And Mozart is pretty good, yeah?
iii goes to vi. iv can go to ii or IV. ii and IV can go to V or vii. V and vii can go to I. I can go anywhere.
iii - vi - [iV] - [V ] - I
[ ii ] - [vii]
EXCEPTIONS: V can go to vi, IV can go to ii.
Note: A complicated chart
In minor: VII goes to III. III goes to VI. VI goes to iv or ii. iv and ii goes to V or vii. V and vii go to i.
VII - III - VI - [iv] - [V] - i
[ ii] - [vii]
EXCEPTIONS: V can go to VI, iv can go to ii, i can go anywhere.
These charts are displayed much nicer in theory books. I recommend Tonal harmony. I couldn't find a picture of it anywhere...
I tend to stick with I-vi-IV-V, with slight variations, but if I was writing a chorale, this is how I'd do it: Say you're in G major (my favorite key to write in). G major is I. I would pick a chord at random (because I can go anywhere), say vi. From vi I could go to either IV or ii. I choose ii because I-vi-IV is over done. from ii I go to either V or vii. I choose vii because I'm cool like that. Then to I. Then anywhere I want!
I hope at least a little of that made sense to someone.
Honestly, everyone else has it exactly right. When writing popular music, you're best to listen to other people. Figure out what progressions you like. Borrow. But, if you want to write something completely unique (you never will), I recommend following counterpoint rules at first. They will help. But, they are just rules. And you know what they say about rules...