My main slide sound is a '70-something cobbled up old SG with almost no frets left on it (actually a pretty good thing for slide) through a marshall/dumble clone rig with some reverb and tremolo. I really like adding a subtle tremolo to the sound because it makes it sound "older" and "swampy". Keep the gain down and the volume up for better articulation and control. I pretty much stay away from gain pedals and just play the amps' distortion. Delay can be fun but it tends to get in the way...
'67 and '74 Fender Twin Reverbs, '74 Marshall 1987 lead mkII, Metro Superlead 100. Pedals from TC Electronic, Ibanez, Dunlop, BK Butler, Electro-Harmonix, Fulltone, Maestro/Gibson, Loopmaster switching, VoodooLab, Boss. Gibson and Fender guitars, Dimarzio pickups.