BookShelf or Floor Standing Speakers


I have previously posted regarding buying bookshelf speakers.  Bookshelf is all I have ever owned.  I prefer speakers for two channel stereo listening.  I am thinking about buying floor standing. 

Has anyone had bookshelves for stereo listening and changed to floor standing?  I am afraid to make the change.  Do you think floor standing gives a better listening experience in stereo?  Can you turn them up very loud?
Thanks
stttt
Not to take this thread sideways but what about running the risk of not getting optimal integration with the subs and stand mounts? I prefer stand mounts for aethetics and mobility but I'm scared of never getting subs to integrate correctly for all music.
After reading your thoughts on this, I have decided to go with a large, or full range book shelf.  I have Dynaudio X18 book shelves now, but would like to purchase some better speakers. 

I am convinced to stay the course with bookshelves.  I want to thank all of you who provided some great advice on here.  You saved me a ton of money and searching.
sttt, you might want to take a listen to Harbeth Monitors. If you want more volume and efficiency Klipsch Heresys. 
gochurchgo,

Two subs are very capable of giving very good bass response at a designated listening position with a pair of good bookshelf speakers on stands. The key is positioning each of the subs optimally in the room. This doesn’t mean just placing a sub next to each main speaker.
It requires precisely and sequentially locating each sub so that there’s optimum bass response at the listening seat. A good method is the ’crawl’ procedure. Once the positioning is completed, the best way to ensure very good integration or blending between the subs and main speakers is the proper setting on each sub of the Volume, Crossover frequency and Phase controls.

If you’re really concerned you won’t get very good integration between the two subs and your main speakers, however, I’m only aware of one bass solution that will virtually guarantee good integration and I use this myself in my system. It’s called a 4-sub distributed bass array system (DBA) and it provides near state of the art bass response and integration in virtually any room and with any pair of main speakers. I just bought a complete 4-sub DBA system called the Audio Kinesis Swarm bass system because it’s easier to setup, at $2,800 it costs less than creating your own DBA by using four self amplified subs of your choice and it works like a charm no matter what your room dimensions and what main speakers you have. Here’s an Absolute Sound review of the AK Swarm that gives a very accurate description of what to expect:

www.theabsolutesound.com/articles/audiokinesis-swarm-subwoofer-system/

If you have the space for these relatively small (1’ x1’ x 28") subs in your room, I’m certain this will work extremely well not only with your current speakers but with any main speakers you’ll may have in the future.

Tim
Thanks @noble100 I’ll be living in increasingly small places (most likely studio apartments) until I drop my body, so the swarm thing is probably too much. As I said I fear I’ll not have the know-how to blend the subs and also afraid that living in stacked housing will make subs prohibitive. It seems from all I read that there’s All kinds of voodoo involved yet everyone recommends subs anyway. Probably just my perception.

i don’t have anyone to help me so if I went this route I’d be going in blind and hoping for the best info that the Internet has.