fmusignac, don't fret, I also have a humble setup, and it's no crime. (I don't even use my sub, bass is directed to F+L, yet my sound is quite satisfying)
The important thing is to know where your gear actually stands in the picture, and that the result satisfies you for the money you've plowed into it. For most of us, the first system build is highly affected by very mundane reasons. Product availability and budget will affect the build just as much as aesthetics and shear "gut feeling" about a product. Most first builds are not nearly as researched as they should be. Besides, evolution can't happen unless you have a reference point. I think your system is a very decent point of reference, and given how well known and ubiquitous your gear is, you should be able to glean a lot of meaningful information to help you improve your setup.
Technical data isn't the whole picture, and the real-world implications of such data also takes time to assimilate. Enjoy what you have, and learn to "know" your gear's "sound", as this variable is just as important as the technical specs and general consensus gleaned from reviews.
The most important things said so far in this thread, I think, is:
The thing with them is the price - for what you're paying, you can do better.
Just my two cents.