FWIW rooms which are dimensionally challenged are not always more of a problem for full range speakers than monitors. It depends on where the nulls and nodes appear in your room and where you end up placing the speakers. Some rooms can have substantial peaks in frequencies at 60hz and above, a range common to most speakers but the smallest of monitors.
Panderso's advise is good. But, I would also suggest that you get a pair of speakers with bass output down to 32 hz to test your room and using a SPL meter and a test disc see what your frequency response problems might actually be. You can, if necessary, probably get by with speakers which are flat at 40-45 hz as you can still tell if you have bass problems at 32hz. There would normally be large stand mounted speakers.
After you do this you will have a good understanding of what type of speaker will work best, a full range floor stander, a large stand mounted with sub, or small monitors with a sub.
Good luck. Take your time!
Panderso's advise is good. But, I would also suggest that you get a pair of speakers with bass output down to 32 hz to test your room and using a SPL meter and a test disc see what your frequency response problems might actually be. You can, if necessary, probably get by with speakers which are flat at 40-45 hz as you can still tell if you have bass problems at 32hz. There would normally be large stand mounted speakers.
After you do this you will have a good understanding of what type of speaker will work best, a full range floor stander, a large stand mounted with sub, or small monitors with a sub.
Good luck. Take your time!