Hi Robin
Really depends on lots of things like what depth of water you are fishing, the bottom structure, the natural bait what species you are after, day or night plugging etc etc. Have a look at the lure forum there are a couple of useful stickys, the lure guide and using lures most of it is based around bass fishing. If thats your target then imho I would go for a few lures that cover the depth of water you are fishing, a top water lure, a sub surface lure, a mid water lure and a deep diving lure. Dont rule out metals either, a Toby kicking up sand has saved the day on more than one occasion.
Good luck with the plugging, but I warn you when you start getting it right, it can become an obsession.
Cheers
N