Bookshelf vs. Floorstand

A good bookshelf will perform better than a cheap floorstander as you suspect and can hold their own against even many good floorstanders, you do need good stands for bookshelf speakers so you must keep that in mind in your choice between the two. That said, if you like the sound of Paradigm 100's (I do)...you won't find many or maybe even no bookshelf that can outperform a floorstander of this size in shear weight and output. With a sub that is well matched to your speakers and room you should have no problem surpassing the Paradigm.

Dave

Give a listen to a pair of paradigm studio 20's with the servo 15 sub. An awesome combination. Sub/satellite combos don't always sound that great though. I prefer the sound of stand mount speakers without a sub the best, however.

If space is an issue and you prefer bookshelf speakers I'd recommend Green Mountain Audio Europas. There are many testamonials on this site that speak to the Europas greatness.

Stands are VERY important. Fundemental extension of your monitors. Great monitors deserve great stands. I have the Revel M20s matched with the Sistrum Mini Monitor Platform System. Now that's a support system. They (Starsound Technnologies) also have another stand (less expensive) that is, also, fabulous. peace, warren

In my opinion the difference between floorstanders and bookshelves (and I mean real bookshelf, not any speaker that sits on a stand) is a matter of taste.
Whilst it may be true that a similarly priced bookshelf is of higher quality (and this is not always true because not all speakers are well designed) your personal taste may be, like mine, that music simply isn't enjoyable without a decent bass response going down to at least 40Hz, no matter how pure the midrange, or crisp the treble.

So I think your question has no answer because it's a matter of your taste in music and your taste in sound reproduction. Some people can live without the bass for a better midrange and treble, and others cannot.

As others have mentioned stands are important, and often when these are factored in (Several hundred dollars) then the bookshelves are similarly priced to the floorstanders.

As for full range speakers versus bookshelfs and a subwoofer I would say that, again, there are no absolutes. I have heard very good and terrible floorstanders, and very good and terrible sub+sat combinations. The one advantage of sub+sat systems is that they can be easier to place in a room, placing the satellites for imaging and the sub to load the room. However good subs are expensive and often drive the total cost above that of a floorstander.