Presiting Mons

Seadra(not bad at all, have a bunch from eggs)
Scyther(common, as are exeggutors in area)
Snorlax(semi common)
Tangela(used all the time)
Tentacruel (not too bad, resilient)
Raichu(self explanatory)

They are not ideal, but they are what I have the most of in the right CP range with the movesets I want.

I like to have multiple copies of the same prestigers so I don't have to go to the menu as often.

Butterfee (Bug Bite, Signal Beam
Raicate(Bite/Hyper Fang)
Raichu
Machamp
Tangela

Vaporeon
Parasect
Dewgong
Wiggly
Snorlax
Venasaur (was Tangela before event)

There's a few more I'll occasionally use (Arcainine, Marowak, Electrode), but the first are the most commonly used for me.

raticate with bite/hyperbeam is nice :)
and i love to use Omanyte/ Omastar

My most used trainers, in no particular order:

Parasect
Vaporeon
Electabuzz
Jolteon
Dewgong
Sandslash
Parasect
Tangela
Pidgeot
Raticate

Wigglytuff is the prestige all-star. Lower CP vapes, dragonites, and snorlax are also amazing.

I have two main teams, a <1500 team and a <1200 team. Because I vary the lineup according to gym defenders, I have more than six pokemon for each team, but a good representative six from each would be:

1500 team:
Tangela (VW/SB)
Seadra (WG/HP)
Wigglytuff (P/HB)
Cloyster (FB/B)
Pinsir (FC/XS)
Magmar (E/FB)

1200 team:
Venusaur (VW/SB)
Raichu (Sp/Th)
Kadabra (PS/SB)
Charmeleon (E/FT)
Vaporeon (WG/HP)
Raticate (QA/HB)

2 Vaporeon W/A- Best generalist and Rhydon / Arcanine (infinites Growlithe here) killer. Also for Snorlax
Tangela and Saur V/S- For omnipresent Vaps and non Ice Puncher Poliwraths
Wiggly P/P- Great generalist and decent against Dragonite
Cloyster F/B- For Dragonite
Scyther F/B- For Exeggs
Jolteon T/T- For Gyarados, Wrath and Lapras
Arcanine- For Exeggs and Lapras

All of them are around 1000/1400 CP. Also, I use some sub1000 mons for occasional low CP defenders, mostly a 700 Vap, a 600 Saur and a 700 Wiggly.

Vaporeon (with HP or AT)
Jolteon (with Thunder or Thunderbolt)
Snorlax (with L/HB)
Pinsir
Golbat
Pidgeot

My favourite mons to prestige:

Tangela (she's beautiful)
Wigglytuff
Parasect
Pidgeot
Pikachu
Raticate
Golduck
Electabuzz
Sandslash
Electrode
Seadra
Jolteon
Hypno
Porygon (just because he looks cool)

I should use my Raticate Bite/Hyperbeam more but I don't, but it's great for prestiging.

Graveler (Mud Slap/Stone Edge)
Seadra (Water Gun/Hydro Pump)
Raichu (Thunder Shock/Thunder)
Cloyster (Frost Breath/Blizzard)
Scyther (Fury Cutter/Bug Buzz)
Starmie (Water Gun/Hydropump)

Hypno and Parasect are also pretty good, but the latter one is a bit weak against the powered-up Vaporeon, sadly.

Unfortunately I haven't got a Wigglytuff with Pound/Hyperbeam yet, but I've tried many times.

I've also heard that Persian is a great and fast prestiger, maybe I should try the cat out.

Wigglytuff
Parasect
Starmie
Pidgeot
Raticate
Tangela