For Gilmour's Main stage guitars, he uses 1983 Fender '57 reissue Stratocasters made in Fullerton CA. His primary guitar from the Delicate Sound of Thunder through PULSE was a Candy Apple Red 57 Reissue Stock save for custom EMG pickups and a shortened tremelo arm.
His main guitar from 1971 through 1985 was a 1969 Black Fender Stratocastor with stock pickups and tone pots from around 1972 (probably from the 1970s bullet truss rod guitar he used as a back up). This guitar recently reproduced by Fender saw numerous changes. Notably a rosewood neck (1962) was placed on it in around 1971. Around 1974 a Humbucker was installed for a brief time with Gilmour butchering the pickup cavity between the bridge and middle pickup. Also around this time Gilmour began toying with the extra selector switch that was used to combine the neck and bridge pickup for a fuller tone. In 1977 he installed a Dimarzio FS-1 pickup with a black cover in the bridge position. This pickup had a hotter response than the stock Fenders ( this version was used to record Animals). In 1979 he replaced the Dimarzio with a Semour Duncan SS-1 pickup for the bridge keeping the stock middle and neck pickups. He also included a Charvel 22 fret birdseye maple neck which was custom ordered and had a Fender logo placed on the head stock (this was used for the Wall). In 1983-84 he had a Kahler trem system installed on the guitar with a locking nut. This last version was the last time the guitar was used by Gilmour until 2006. It sat on a wall at the Hard Rock Cafe in Dallas Texas. In 2005 Phil Taylor received the guitar back from Hard Rock and had the guitar refitted with a 1983 57 reissue neck and the stick Fender bridge/trem assembly. Charlie Chandler in the UK did the work resurrecting this rock guitar icon. In 2006 David Gilmour used the Black Strat live again for the first time in over 20 years at the Live 8 concert and subsequently used it to record his live album "On an Island." It has since become his preferred guitar again.
Along with the Stratocasters Gibson Les Pauls, and Grestch Duo Jets are used by Gilmour. He has also used Fender Telecasters most notably on Animals and the Wall.
I currently own three Stratocasters. The first is a 2000 Fender Strat with a EMG DG-20 pickp assembly. It was originally a Sunburst guitar, but I reliced it and painted it black. I chose this guitar configuration because in the sunburst color, it is the same wood used on the '57 reissues, and for the cellulose lacquer used on the fret board. The EMG's offer clear sound, no 60 cycle hum, and the added feature of the SPC and EXG tone expanders which further the ability to shape the tone of the guitar. The SPC acts as a Mid range boost, while the EXG acts to boost the Treble and Bass. This guitar has since been repainted black and the back of the neck sanded down to give it a feel akin to the 57 reissue necks.
The next guitar I have is a 1999 1957 reissue Stratocaster in Dakota Red. This guitar is probably one of the best guitars I've ever played. Everything stock.
I also have a '60's reissue Strat from Japan. This guitar is Candy apple red with a rosewood fret board. I installed Fender lace sensor gold pickups to duplicate that 50's sound. This guitar replicates the very first candy apple red Strat that Gilmour had used. I've also modded the pickups with a toggle switch to give me the neck and bridge positions in tandem. See my Mod page on this for more details.
For acoustic, I use a Fender Stratocustic guitar. This is a nice sounding guitar with nice resonance. Not as pricey as the acoustics Gilmour uses, but adequate for me.
For cables I use Pete Cornish Cables from my guitar to the effects and from the effects to the Amp. I also use Pete Cornish Cable for my HIWATT Amp to my homemade speaker cab. Cables are often overlooked by many guitarists. They are as important as the guitar, amp, or effects used. I was utterly amazed at how much tone didn't get through from "monster shop" cables, and when I plugged in using these cables it was like my guitar was finally breathing. Mr. Cornish relayed a little story about his cables to me. In 1992 Mr. Cornish sent one of his guitar cables to Lou Reed when he was in Japan. Lou Reed phoned him back to say "you put a tone circuit in this chord?", Pete replied, "No, you are now hearing the guitar as it should be..." "OK replied Lou Reed, send me 4 more"
Cables do make a huge difference in tone, or "releasing your tone."
Link cables I use Pete Cornish Links.