At present I have two rooms with halogen downlights (so there are already holes in the ceiling) and want more downlights in a long hallway. I know all about the heat problem with halogens as some actually burnt out. Had the electrician in last year and wanted to change the kitchen lights to central light fixtures; and priced that at first before asking on this thread for input. For the kitchen I could easily spend 3 - $500 on one or two traditional light fittings, plus the installation cost, plus plastering and painting the holes over; so I reckon it will cost just a little more in LED fittings plus electrician.
Same will apply to my office, only one surviving halogen downlight, out of three - a central ceiling fan, which I could replace with a fan with a central light - again this would be costly and holes need to be plastered over, painted etc. and - once again would be lit by traditional filament globe, possibly CFL.
Thankyou all - for your posts - when I have more time, I'll try and put all your good advice into one message and post.