Speaker upgrade time? (from PMC GB1i)

My main music listening system is my my living room, so it has to fit in with the wife and kids. My budget for upgrades is not huge, but I’d like to start thinking about what my next move will be when I have the cash.

I listen to CDs only with my Leema Stream 1 and Leema Antila 1 amp with PMC GB1i. My room is 3.2m x 6.6 with the speakers on the long wall firing across the room width. I am limited in how far I can pull the speakers out into the room.

I would like to have a plan for my next upgrade and have been thinking it will probably be my speakers, but where to start? I would like floor standers again (for aesthetic and kid proof stability reasons), but they need to be unfussy about positioning and happy fairly close to the rear wall. My GB1s are very good, but I feel my amp has more to give. I am likely to be looking at ex-demo or secondhand.

So what speakers might I consider which suit my requirements and give a decent performance jump up from the little PMCs?