Local Network ip address naming convention

So I came into work today for a big surprise only 3 of the 8 computers could get on the internet. Joy!

So after a little googling I figured out that the computers that worked had static IP's and their preferred DNS servers were all set to the same thing. The rest of the computers had different DNS server settings and thus were not working. I'm not sure what triggered this or why/how it was working fine before. But thats not the issue at hand.

There seems to be little or no convention to the static IP naming convention here.

Here's the current setup

Server 10.250.250.11
Receiving 10.250.250.7
Shipping 10.250.250.4
Website 10.250.250.105
Bosses PC (uses DHCP)
POS 1 10.250.250.100
POS 2 (uses DHCP)
POS 3 (uses DHCP)
Printer (10.250.250.244)

Current DHCP range (100-149)

Used to have a Linksys AP WAP54G connected that was on 10.250.250.245 but there is no need for wireless at the moment so i disconnected it. Our IT company apparently used it for easy access. So they could walk around with a laptop and fix things.

I want to give this some structure!

I'm thinking move the server to .2

Move the rest of the PC's to .10~16

Move the printer to .50

This would allow room for expansion of servers or what have you from .2-.9
PC's from .10-.49

and printer and other hardware from .50~.99 (we have 10 other non network printers that may one day become networked)

Now I'm not really the IT guy, but I worked for the IT company that manages these PC's so... I do what I can and hand off the hard stuff to them. I feel this is something I can manage.

Naming convention sound ok? Or does it look like a novice's work.

This should work, but why not use DHCP for PCs? If you do, make sure the DHCP configuration points to the correct DNS and default gateway.