IMHO the Wilde/Bill and Becky Lawrence L280 noiseless pick ups are the best drop-in replacements for the sake of fat tone and clarity.

The Dimarzio Area T pickups are a close second. They might get you closer to the classic Ed Bickert pre-PAF tone, if that's what you're looking for, than the Wildes. Having used both extensively, I prefer the Wilde pickups.

Both of those have a bit of humbucker compression; if you really like the true single coil sound, the Wilde Microcoil pickups for the Telecaster are outstanding. While they are a true single coil, they pick up less noise due to the smaller coil not offering as much antenna. There are two versions, one with I presume a ceramic bar magnet and one with alnico polepiece magnets; I prefer the sound of the ceramics (the alnicos are a little too Stratty for my tastes).

In my case, I have found that I like adding a resistor in parallel between the hot output of the bridge pickup and ground to sweeten/round off the highs just a little bit and make it less spiky. There are wiring diagrams on the Wilde website and also Lindy Fralin's website has a very nice page on this. Basically, this makes the bridge pickup think it is seeing a lower resistance pot, say 100K, while the neck pick up thinks it's seeing 250K. Folks who belong to the icepick school of Telecaster bridge pickups would probably hate it.