A home that looks like it has been a collection over time is not the same as eclectic. Let me show you the difference.
It is easiest to show you homes that do not look like they have evolved over time. I call these nouveau riche, meaning new money. Another name I have for it is Tacky Tuscan. ;-) I have a couple of pictures of homes for you from the New Housewives of Atlanta, where, in the one and only episode I have ever watched, I saw all nouveau riche design.
I see matching sets, a lack of antiques...
All brand new furniture, again, no antiques, no classics, match, match, match. These are homes that could have easily been decorated without an interior designer at all.
The architecture lacks interest. Rather it says to me, "Look how large I am, look how high my ceiling is!" But when you look closely, it looks like a glorified magnified tract home. This look was not collected over time, it could have been collected in a long weekend shopping spree.
As a contrast, look at the room above. Do you see any matching sets of case pieces or upholstery? No. Does everything look brand new? No. It might be, but it doesn't look it. That's the point. The opposite of the tacky Nouveau Riche look would be what I would simply call, Timeless.
Eclectic is referring to a different principle altogether. An eclectic look is created when you combine different styles. For example, the Asian busts combined with the modern art above- is a perfect example of eclectic. This is also an example of design tension. There is overlap in the two thoughts. The real difference is simply that design tension is more extreme.
For another example of tacky thoughtless decorating- check out Dr. Phil's house in this post.
The top three photos of The New Housewives of Atlanta are from celebrity Digs. The other photos are from Architectural Digest.