MasterQ;
Just so more people can follow along, I am going to outline some things that you are probably painfully aware of.
Cabling:
10 Base 2 cable is 50 ohm coax, with BNC connectors.
10/100, more properly referred to as 10 Base T and 100 Base T, require Cat 5 UTP cable.(10 Base T can use Cat 3 cable)
Both are Ethernet.
NIC:
Most, but by no means all 10 Mb Ethernet cards shipped with a 15 pin D transceiver port along with a BNC. A 10 base T transceiver can be used with the AUI / DIX / Transceiver port to use existing NICs at 10 Mbps.
New NIC's are almost all rj45 only, and are 10/100 compatible.
Hubs:
Hubs are generally obsolete for new Ethernet installations. However, if you attach a 10 baseT transceiver, it is important to disable "heartbeat" on the transceiver to avoid a 50% collision caused by the incorrect configuration.
Brands:
Cisco, Nortel, Extreme, Foundry, and others make excellent switches. I would avoid 3Com, due to the lack of commitment to the enterprise network market.
If it were my network, I would rip out the 10 Base 2 network and forklift upgrade. However, its rarely an option.
If you have specific questions, let us know.
Just my two cents.
Doug