SoltisViolin
Welcome to the boards. The subject of plugins is one of debate with PS users. If you use PS for enjoyment and fun they are great. If you intend to become an expert, the general consensus is to learn how to create the effects you are after using the tools available in Photoshop. Tutorials are the way to go. A Google search will help there. For example, run a search using the terms, 'Photoshop drawing tutorial' and be prepared to be overwhelmed.
About plugins. I like them! As MsOz points out, you need to decide what your goals are and then give them a try. Almost all plugin creators have demos available. Since you asked about Eye Candy 4000, I'll start there.
Eye Candy 4000 is a large group of filters which are all OK to pretty good. If you were wanting professional, original results, they probably aren't quite what you would want. AlienSkin is rewriting Eye Candy. The new versions, Eye Candy? 5: Textures is a plug-in collection of 10 texture generators. The first of three upgrades to Eye Candy 4000. They are significantly better than Eye Candy 4000 but will be expensive if you buy them all.
http://www.alienskin.com/
One of my favorite plugin creators is FlamingPear. These are great fun and can be used in a professional environment. SuperBlade Pro is one of the best texture generators ever but takes some learning. Flood is plain fun. There are several bundles which are worth checking out. Click on the purchase button to find them.
http://www.flamingpear.com/products.html
Andromeda has quite a number of older plugins which are quite good. Some of them have been updated, some have not and won't work with PS CS.
http://www.andromeda.com
Power Retouche Photoshop plugins for high quality photo editing, retouching and image editing. These are professional quality.
http://powerretouche.com/
I've saved my AutoFX suggestion to last because, were I buying plugin and graphics software today, they have a bundle, Creative Extreme Bundle which includes 5 pieces of software.
DreamSuite Series One
? DreamSuite Gel Series
? KnockOut 2.0
? KPT Collection
? Bryce 5.0
This is a great collection of PS plugins with Bryce thrown in for $199.
Cheers!
Welles