For lighting control it depends on how many separate circuits (groupls of light fittings) are required plus number of keypads. Unitl those numbers are known it's impossible to give any meanigful budget prices. Most have infrared & RS232 for control by any number of touchscreen/tablet remotes as well as volt-free input interfaes to link to security alarms etc. Colour change can be by propreitry hardware for by hidden red, green and blue fittings and mixed simply by adjusting the individual dimming levels. Any multiroom lighting control system will meet your basic requirements although most (if not all) will need to be supplied and programmed by a local dealer. I supply Helvar equipment and can recomend their Digidim system (see
www.helvar.co.uk for details) but you will could also consider Rako, Lutron GraffikEye & Homeworks, Mode and lots of others. There will be small differences between them but the main feature sets are pretty much identical.
For music I would recomend Sonos, you can buy it from any number of retailers and it would work with just about any NAS device. Note that this has it's own remote control and cannot be controlled by other systems or control other systems. There is a PC-based control app that you could use as well.
Velux supply their own electrical motor/control unit for window and blinds and it is possible to interface some of these with the lighting controls for automated operation.
Touchscreen control could be through Philips Pronto or URC MX-3000 - both are infrared remote controls with optional radio receivers for remote/hidden equipment. If you go down the RF route then you would wire in an extra lighting keypad or IR receiver to provide control of the lighting, windows etc
For ultimate control take a look at Crestron or AMX - expensive and supplied by specialist dealers who will program the system for you.