I kind of like the cinder block edge. But I live in a loft, where such details are prized.

I thought I was the only one with that problem. I took down a wall in my apartment and was shocked to find out that the brick only went 2/3rds of the way up. The rest is cinder block.

I covered the cinder block with sheetrock and put edging where the sheet rock meets the brick. To do this I took 1X4 pine and attached it to the cinder block using construction adhesive and masony attachers. I then screwed the sheetrock into the 1x4 pine. If the cinder block is even enough you may be able to glue the sheet rock directly to it.

If you have a lot of money to burn you may be able to find a mason that can cover the cinder block with historic brick but it's probably not worth it.

big moldings or faux painting...someone else, maybe on this site, just showed where they fixed a large crack in brick by faux painting, you really couldn't tell the difference

You could just paint the cinder blocks and leave the brick. It might look nice if you extend the color you choose (not white) onto the ceiling about a foot or so as well.

Depending on your style- stainless or galvanized sheeting going around the top could look good OR slightly raised molding or wood planks with lights behind them creating a cool glowing effect.

Why not just paint it?

My mom, whose design sense is eclectic, would do stripes of bold color as suggested by rows of cinderblocks, or would go one further and paint the whole thing one color and then drop in blocks of contrasting color corresponding to individual blocks.

Personally, I might be inclined to paint the ceiling and cinderblocks all one color. I'm sure you could find a color to your taste that would go well with the brick.

Big crown moulding... think: coved ceiling meets right angles.

I agree with painting the blocks...If you want to hide the shape, texture and morter lines to better blend in with the ceiling you could do a thin skim coat over the blocks and then paint the same color as the ceiling.

I agree with Lisa Hunter- I would just leave it. Speaking from another loft liver.

plaster and paint.

Second JamieZ

How about those 1/2" thick bricks that are meant to make brick facade over an existign structure?

Ditto on the Plaster and Paint.

what about painting the cinder blocks one of the brick colors?

choose one of the mid-tones, and i would be tempted to do a glaze(water and acrylic paint or oil-based plus ?) that would permeate the cinder block.......let the texture and imperfection of the block come through. i would not prime first.......you won't get the same rough look.

forgot to add...........find a "spare" cinder block, and practice on it. you may have to do a couple of coats.......

I like the paint idea too. I'd either do white to continue the ceiling or do a dark color, like a really dark brown and leave the ceiling white. I like the idea of leaving the texture somewhat visible and I think regular paint would allow that.

Trim, plaster level with surrounding wall to hide and then paint. Or, Uncover all of it and then use wide boards to cover. Paint to match other trim. Rather like a deep crown molding without too much funky detail.

I'd be inclined to strip it or paint it the same color as the ceiling--but I would make no effort to conceal the fact that it's cinder block. Actually, yeah--I'd clean the cinder block up and leave it as-is, and I'd install a picture rail made of of flat bars of brushed aluminum or stainless steel over the joint between the brick and the block.

Get over the attachment to the notion that having the brick go all the way up would for some reason be more desirable, and learn to appreciate wall for what it is.

Something that had not been mentioned yet is the idea of a dropped coffered drywall ceiling that comes down to the brick level. You could have some recessed lighting in the ceiling, similar to how you would do it over kitchen cabinets. This is a more expensive option, but then you would also have light to highlight your new exposed brick and the artwork on your walls!

I should have clarified that the coffered ceiling I was thinking about would come out into the roof maybe 18-24".

Why don't you simply put shelves covering the cinder blocks?, you'll get space for your old LP's and you can also add light to the bottom of the selves to show your brick, as Quince suggested.

I like the idea of shelves or a picture rail - Hoyt Clagwell has it right. Acknowledge was it is and make it look good. if it annoys you in a year then you could do the plaster thing, but it seems like a lot of effort and you still wouldn't have a seamless look.
I think it could look really great though, with the shelf/ picture rail distracting from the different materials, and adding character and function to the room.