First, if you are getting fret buzz at the top and bottom of the neck, it is possible your neck may be too straight. Place a capo at the first fret, and then press on the last fret of your low e string...there should be a clearance between the top of the 8th fret and the bottom of the low e string roughly the size of a .010 string. If your string is touching the frets your neck is too straight.
Also, measure the height between the 15th fret and the bottom of your strings...it should be about 2/32" for low action (take the capo off and don't fret any notes).
My guess is that your neck is too straight. Also, lighter gauge strings and low action will tend to give some fret buzz too. If I'm using 9's on my guitars, I usually get more buzz and have to raise the action a bit.
Guitars: 2003 and 2004 American series strats, Squier Classic Vibe 50's Strat, Squier Deluxe Strat.
Amps: Line 6 Spider IV 120, Vox AD50VT 212, and Peavey Transtube Bandit 112.
Pedals: Digitech Bad Monkey.