Bookshelf vs. Floorstand

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.

I second Sean99. Subwoofer is essential. It's only a matter of ( a short) time 'til you'll realize that you're longing for what's below 40Hz. As you can see, I use a sub, as well.

Yep, same here. I use a sub/sat combo as well. Monitors with a sub allow you the flexibility to set up both independently so you can maximize the performance of each. However, finding the right place for the sub will require a lot of experimentation, and integratin gthe two isn't easy.

Just for the record I use floorstanders (Spica angelus) AND a sub !!!!! (Belt and braces). Many floorstanders only go to around 35Hz and can benefit from a good sub to fill out the really low stuff. For monitors I'd view a sub as essential.

Just out of interest do you have a budget for speaker upgrades, because then some others might be able to give actual suggestions.

Well... space is not an issue because my room is 22 x 20. I have personally compared the Sonus Cremona Auditor, Grand Piano Home, B&W 804 and Studio 60's and I should say that the Auditor creamed all of them in terms of mid range (well according to my taste). However, it does lack in bass and I figured that it can be addressed by a sub while a good mid-range comes with the speaker itself. Now what I cannot stomach are the stands - $1000 for the sexy Cremona stand! Actually I was planning to match it with a cheaper stand but hearing you guys mention how important stands are for bookshelf speakers I want to know more. Cant I match the Auditors with cheaper $100 stands? What is the net effect? Honestly I'd rather spend the $1000 for the stands on the speaker (i.e. a floorstander). For me that is better value but the mids of the Auditor are just to die for :)

Dilemma dilemma. If I go floorstander then I chooser between the 804, Grand Piano or Studio 100s. Which one???