I have built many computers. I love Dual core, the computer I currently use out of my home is an AMD dual core x2. Very reliable and stable (surprising for windows, i know, haha) Works wonders with XP 64bit edition.
You definately have to know much more about computers to use Linux, but if you are knowledgeable in that subject I think its much better than windows. Fewer crashes and more reliable in my opinion.
You definately have to give firefox a try. Its really simple. I love the fact that it saves frequently visited pages in Cache, so images and large banners and such load much faster...nice little perk.
Haha wonder what dirty people clicked on this topic cause they had different kinds of "positions" in mind. Cute kitties though. Great pictures, I think I got that in my email once?
Definately have to go with cable...althought that is broadband too..? your question was a little confusing. If you're still using 56k dial up I have great mercy for you. I think its time to upgrade..
A computer i built about 4 or 5 months ago:
AMD x2 4400+ Dual core
2 GB Corsair memory
320 GB hard drive
Geforce 7800GT
Dual Layer dvd burner
Asus Premium motherboard
Dell 24" Widescreen monitor
Not too bad. I've built better, but it gets the job done, haha.