If you enjoy hunting and collecting custom content (like I am), you can't really limit yourself to a particular artist, you'll miss too much. But you also can't just go for it, because pretty soon your game and/or comp will get sluggish ;-)
Here is my advice how to organize your PlugIns (with all the pros and cons up for discussion):
Create a 'Basic plugin-pack' containing all the must-haves to create a city/region, i.e. a good array of stations for your preferred transportsystem, civics, educational, utilities etc., don't include any RCIs here! You may also want to include a folder with the most common Essentials, Textures, Mods and Prop-Packs (though it takes some time to learn which are really common).
Run some tests and discard everything that is not absolutely essential to develop a basic city. Once you got that down, create a whole set of Add_On_Plugins, structured in various folders/subfolders. I've got things like Highway-pack, Park_Plaza-pack, Rail-Pack (with subfolders like El-Rail, Subway, Monorail etc.), Harbour-Pack, Rural-Pack, Building-Pack (again with lots of subfolders for R,C and I), Waterfront-Pack, Canal-Packs, Landmark-Pack and so on, you get the picture. Since they are not ingame, you can run wild on the folderstructure – the deeper you lay it out, the easier you'll find stuff later and the easier it will be hunting for particular missing items.
I found it easiest to store all my addons on an external drive – as my city/region develops, I just copy the needed/wanted 'add-ons' into my ingame (basic) plugin-directory (where I have a special folder 'ADD-ONS'). When I'm ready to move on to a new Map, I just store the old Map plus the ADD-ONS-Folder on the external drive. Should I want to work on it again, just copy those two back again (into my 'Basic_Plugs'). That way I have 'City_Packs' with nothing but the needed Plugins, and, not to forget – rather lean ingame menues.
Maybe sounds a little complicated, but it is not really so. And the reward is a fast-moving game and easy-to-handle menues. And you'll never again have to worry about downloading 'too much' – just stick the new stuff in a TEST-folder first, then –if you like it– distribute it to your various ADD-ONs, ready to use any time. Just remember to keep your basic set clean and neat, change/add items here only when you are convinced that they are really must-haves for EVERY city you start. My aim here is to rather compress my 'Basics' more and more – with every city I develop I can identify some more stuff that is not really essential.
As for collecting – I'd suggest, you hunt first for all content that comes with 'No Dependencies'. Believe me, there is more than enough around. Later on you can look for those very special pieces that may be worth some (of the more 'exotic') dependencies. You should always judge if that particular piece is really a focal point in your city and so merits many megabytes of additional code – more often than not a piece just 'disappears' among rows of other buildings, so sth. more 'light' would do as well.
I'm not adverse to dependancies (I figure, I got all, well most, of the available packs) – however, I find it rather taxing if I have to load 3 or 4 Megapacks (equal to about 30 to 40Mb) just to display a forklift and some bushes. That adds up fast, take 10 buildings like that and you have (mostly) useless 400 or so Mb in your memory...