I'll have to agree with Moonlapse that the Waves Diamond bundle is probably the most convenient and useful bundle of plug-ins I've ever had the pleasure of using. It's my main artillery for every session. However, lately I've been using some freeware plugs made by some guy that calls his "business" DigitalFishPhones. The Fish Fillets bundle is pretty damn useful, and just as good as any other three counterparts out there I'd say. The BlockFish is a great compressor, and even though I love the Waves RComp to-freakin'-death, the BF has given me the right kind of compression I've been looking for on my snare drums. The RComp is an indespensable compressor to have laying around, great for just about anything you put it on, but I haven't found the right settings with it (after a few years of using it) to get the comp I want like I get so easily with the BlockFish. Also, the SpitFish plug to get rid of sibilants on tongue-y vocalists works amazingly well, and again, a little easier to use than the Waves counterpart. The FloorFish is a great noise-gate that I've found many uses for, most notably for drums. In all honestly I'd rather use the Waves plug for that, but it's still useful to have laying around.
Also, the Waves SSL series is an amazing recreation of the SSL stuff. the first board I ever worked with professionally was an SSL9000. The best sounding board in the world, IMO. I've also traveled to a few studios around the US to do work for my old boss and had the opportunity to mix and record on Trident consoles. The first time I heard a snare through that SSL console, I almost died. Pretty much anything that goes through those pre's sounds amazing right off the bat. Anyway, the Waves SSL series EQ and Compressor alone are worth the cash.
The UAD-1 and PowerCore bundles are cool too, I haven't had the chance to use them personally, but people I trust have and I know if they say it's good, it is.
Ah yes, the good 'ol PSP Vintage Warmer. Another indespensable plug to have. I've used it many a times on vocals and drums. One thing to that though, and I learned this from my boss, you gotta bring your "A" game when you use that thing. It's very surgical, which is a good and bad thing. If you know what you're doing, you can get it going, if you're kinda lost...you'll get frustrated with it. That's just how I look at that plug though. It's probably one of the most extensive comp plugs out there, lotsa options on it. Still cool though, and really does add some analog style vibe to the tracks you put it on.
The Sony Oxford stuff is neat too...although I usually go right back to one of my Waves plugs instead...not a big difference in the Sony stuff, nothing to write home about or anything, nevertheless though, great plugs in their own right.
Also, if you have Digital Performer, the MasterWorks Comp, EQ, and Limiter are really great. I'll be honest again though, the MW-EQ is probably the only one I use out of the three. The MW-Comp and MW-Limiter don't get much use from me. I'd rather have an L2 and an RComp or BlockFish.
Typically, the first EQ I go for at the studio and at home, is the Waves Rennaissance Q-8 or Q-10. The first comp I go for is the BlockFish, and if it's just not cutting it, then switch to the RComp...and if that's still not working, definitely the Vintage Warmer. Especially on vocals, I grab the Vintage Warmer first on those. For bass guitar and kick drums (and sometimes toms) always the Waves Rennaissance Bass or MaxxBass.
Anyway, that's my rundown.
After all that is said and done though I'd still rather be back on that SSL console with those channel strips, and have a lot less use for plug-ins. But hey...gotta go where we're happy, or at least I did.
~006