Perfect tone is subjective. (BTW This is not how Gilmour gets his tone)
A decent tube amp. (I use a Mesa Triaxis into a 100/100 6l6 Marshall Poweramp)
Guitar -> Preamp -> Time based effects in the loop run in parallel -> Power Section -> Speaker Cab
If you want effects in front of the amp get a loop switcher(GCX or Loop from Tonebone) which can take the pedals in and out of the signal path.
This will get you in the ballpark of Gilmour's sound
Guitar: Am Vintage Reissue strat with a DG20 set from EMG
Amp: Gilmour uses multiple HiWatt amps to create stereo effects but a decent Mesa/Boogie Lonestar or Stilleto would get you close. Or try the Triaxis setup I mentioned above.
Effects: Gilmour uses Big muffs, pro co rats, boss sd-1's, ce-1's, Space echos, tape echos, etc. A TC G-force will cover a lot of the ground for you instead of buying individual effects. Then you can add in anything you find is missing/not quite what you need.