If you're tight on space, in-wall speakers can be a good option, but I'd recommend getting sealed units that have their own enclosure. This is essentially like placing a shallow bookshelf speaker inside the wall, and will give far better acoustics that an unsealed unit. Definitive Technology has some good options in their UIW line, as do many other manufacturers. Let me know if you need any help picking out some appropriate options, and I'll be glad to assist in any way I can.
Take care,
-David
Take care,
-David