Free Advice and thoughts
I try and give unbiased advice and ideas as I have many years hands on experience, so here is generally what I think about specific areas, although I may have different solutions or ideas based on information I am given and the environment it will be used in.
PC's: I have seen and used many different manufacturers hardware over the years and now generally recommend Dell. Of course other manufacturers should be fine, but should there be an issue, it seems Dell actually do pick up the phone and provide quality support, with next day swap out etc. From my experience you do not get such good customer service or quality hardware from other manufacturers.
Security: Although the free virus and firewall tools from AVG and ZoneLabs are fine, I dont think the security of your pc should be treated lightly. The big names such as Norton and McAfee are good products for a reason, therefore I always recommend them if your pc is well spec'd. Norton Internet Security 2011 for example includes a:
Firewall - Stop anyone accessing your pc
Antivirus - Keep pc's free from Virus
Spyware - Remove malware that includes popups, key trackers etc
Spam Blocker - Redirect spam email away from your Inbox
Broadband\ISP:
Again, based on my own, other users and other technicians experience from various places of work, it seems you will have less problems if you choose BT to be your Broadband provider.
BT - Because they own the line into your house and will be your provider there is no problem talking to a middle man should there be issues. They seem to have the most reliable service.
AOL - Tries to tailor your internet experience, by installing toolbars and start up processes that drain pc resource, and branding your internet explorer. AOL disks only use are as coasters for your coffee.
Of course any pc or ISP you choose should give you trouble free use, and I do have users on AOL or using Toshiba pc's for example that work very well, but I never seem to have to visit BT and Dell users as much as all the other brands and makes.