Most of us would connect a Mac mini to that TV permanently--and then screen share in wirelessly from another Mac to control it or use an iOS device like an iPad as a remote control. If you can afford a 46" 1080p LCD for the kitchen, what's another $500 for a mini?
That said, a $99 Apple TV would be a nice, inexpensive option to get music, video and Netflix to the kitchen, it's not as comprehensive or capable as a Mac, it can't display websites or recipe files, yet, but it is less complex and much easier to operate and control.
It's tough to do what you're trying to do with just the one Mac in the house--there's no way to extend a desktop or add a second display to a laptop wirelessly--some device has to be connected to the TV (or built-in to the TV) that's networkable, smart and capable enough to receive information from your Mac. If you do just have the one Mac and the budget is tight, connect it to the HDTV and then control it with an iOS device, if you don't have an iPad yet an iPod touch or iPhone makes a very nice remote.
This is also why you're starting to see TV sets ship with internet capability and various media apps, like Netflix Instant Watch, built-in. Some sets manage to do this fairly well, we have an LG with Netflix built-in and it is quite nice, not as seamless as Netflix on the aTV2 but very close. Media sharing from other networked Macs and PCs, well, most Mac users would probably find the TV's ability to share media somewhat frustrating. Not sure how good your Samsung is at that.
I liked it better when TVs were dumb displays.