Based on what would appear to be your lack of experience with this sort of stuff, I would suggest you find a good and reputable custom install shop in your area and make an appointment to go talk with them. Bring with you a list of your equipment if you don't have it in your head, and tell them what you need /want to do. They should be able to get you going in the right direction or at least give you some food for thought while they give you the sales pitch. If they really know what they're doing they'll ask you questions more than they talk at you. There are many control systems out there that will let you lighten your wallet considerably and give you the ability to dub from the living room VCR to the bedroom VCR, something useless for most folks. There are also many that are very reasonably priced and give you a reasonable set of controls. Retrofitting your existing house to have a Via! system running your HVAC, lighting, and security won't be cheap. You might find that you want someone to install this for you after you speak to a pro, but if you don't, you'll at least gain some knowledge.
If your goal is to be able to switch between sources, have control of the volume knob on your preamp, and have rudimentary control of sources (track up/down, play, stop) then there are literally dozens of products from well respected and well supported companies with good reputations. My personal favorite was always Xantech for basic control systems, but the Via! by Elan is very nice, it's just more $$. Elan tends to like to work with their own control hardware, whereas Xantech has generally made more products that can be added on to what you have. Elan is great for an 8 zone/ 12 room system with integrated phone paging, gate opener control, and low voltage lighting control, but generally a little more involved and more $$ than someone who just wants some control from another room wants to spend.
As an audio hobbyist, you are likely fully capable of the install of a basic system like this yourself, but where I would caution you to get the advice of a pro is in the design so you ensure reliability and ease of use. Also be aware that if you do it yourself there will be some painstaking programming possible (similar to a big universal remote), whereas the installer would do it all with a laptop interface that makes it much faster. Some high-end audio gear has oddball IR control coding as well, so often these "finicky" pieces are better controlled by RS-232 interfaces if available, and in some instances, where the item operates on a whole different IR system, IR modems are available to make a keypad designed for the norm talk to the oddball piece. Some companies discourage sales of their products direct to consumers, too, so you may be forced to have it installed for you.
Many companies now offer "pre-fab" kits, too, for example the Xantech kit that has been around for years and years that will allow you to use existing coaxial cable from point A to point B to control sources at A from room B with IR remotes (while that coax still carries CATV)-- you can buy all the parts to do this in a single box with instructions.
Lastly, some of the user-configurable LCD panel based "universal" remotes have RF kits available that make them an attractive multiroom control option. You could configure this yourself and just have it with you in whatever room you're in or sitting on a desk in its recharger cradle. The Philips Pronto for example plugs into your laptop and that's how you program it with codes available for free off the internet. If the codes for your oddball pieces are not available, there are other ways to "teach" the Pronto the codes.
The nice thing about all this control stuff is there's no adverse sound quality impact. Be advised, however, that there is a big difference between multi-ZONE and multi-ROOM audio. Multi room is the same source in several rooms, multi zone is a different source playing in each of several rooms. Not sure which you need, but if it's multi-zone you'll need a preamp designed for this and more amp channels. Multi-room you'll likely want a small amp or integrated to feed signal to at line level so you don't adulterate your hi-fi rig with speaker switches, etc.