|So my plan is for a new modem, new router, switch for extra ports, replace all cables with cat 6, new 10/100/1000 nic cards. Did I miss anything? (besides a fat wallet)|
Pretty much all unnecessary!
You don't need a new modem or SOHO router. As has been stated previously by others, this will not improve your internet bandwidth.
You can however improve LAN bandwidth by purchasing a 1000 Mbps switch and plugging it into one of the LAN ports of your existing router and then, plugging all your client computers into said switch. Once all clients have 1000 Mbps interface plugged into a 1000 Mbps switch, they will communicate with each other at 1000 Mbps
Save yourself some money and keep your existing modem and router. If you're already using Cat5e network cables, you don't need to go to the expense of purchasing Cat6 since Cat5e can, and does, carry 1000 Mbps.
So to repeat, all you really need to buy is a 1000 Mbps switch and 1000 Mbps network cards for any/all PC's that don't already have 1000 Mbps interfaces.
As StuartS pointed out above, if your PC's are clogged with crap, that will slow them down. Simply downloading and installing a good antispyware application (like Malwarbytes) and running it every day or two, will help resolve that issue.
Keep in mind also that even if you did upgrade to a higher bandwidth internet package (assuming it's available to you) that still doesn't guarantee faster downloads as you are still victim of the servers you download from. If the server is real busy, it will be slow.
I have a 30 Mbps (enterprise level) fibre optic connection to the internet here at work. I tried to download a couple drivers the other day for a computer and the mirror site I first connected to told me it would take over 3 hours to download the one file. A file which should have taken about 2 minutes to download. The problem was the mirror site was totally busy. I tried another mirror and voila! I had the file in under 5 minutes.
As for your bosses whining about how slow it is, tell them to stop whining. They're not on dialup using a 1200 baud modem! They should feel lucky the have what they have.