Only Shapes said:
Is there a way that if I had the router right next to the imac I could have a direct connection with ethernet cable from imac to router?
Hmm, yes. You don't
have to use wireless with a wireless router.
Also, you don't
have to use a Linksys router with the Linksys adapter on the PC. They should be fully interoperable.
That said, there has been a hell of a lot of problems with wireless routers. If you read reviews of them, they either work very well with a particular set up, or don't work at all. For instance, when I was researching wireless routers, just about every one I read about had either zero stars or five stars. And often they would work for 3 or 4 months, then stop completely.
I went with a Netgear wireless router about two years ago and have had no problems connecting my iMac (with the built in airport, at least without encryption - see below), PC laptop (with Intel wireless G card), and desktop PC (with added Linksys PCI card).
Lots of the new Intel Macs, mine included, have had problems with slow wireless connections when using WPA encryption.