Thank you both for your help.
I will be buying all new cards either G or N, so I will take price/power into consideration when I buy.
I'm guessing you've just seen it talked about all over the place? Yeah, I have read a few topic here about the Asus RT-N16 + DD-WRT making it into a powerful router. In fact that was the main reason I asked about matching router & adapter together, because I couldn't find any matching cards for the Asus RT-N16.
Stability was the only main feature I noticed that would help me out in regards to DD-WRT. I Just wanted to make sure I wasn't missing anything major. I never use any type of BitTorrent, gaming is the heaviest load I will but on the router.
I can't comment on the range of the newer internal antenna N routers, as I only installed one so far at a friends house. Perhaps someone else can shed some light for you. I will wait for a bit and see if anyone else knows, if not I will just give it a try. I miss the old removable antennas in a way.
Thank you for everything, I know I could get DD-WRT up and working if I wanted to, but by the sounds of it I wont be missing anything major. I will be the first to tell you I don't know much about networking and even less about DD-WRT/Tomato (Less then 24 hours) Normally I like to research stuff a lot more before I buy, but I don't like having an unsecured router and can't seem to fix it. I will upgrade and fix the problem at the same time.
Thank you