What is the best LAN desgin?

Floor A is reserved for top management, marketing, and sales (including product
demonstrations); only about 50 employees work on this floor.

Floor B is used by the 75 employees of the administrative functions (finance, accounting, and
HR), and

Floors C and D are utilised by the consulting/software development teams.

The building has been wired according to the ANSI/TIA/EIA-568-A standard so that on
Floors A and B each workspace has two data ports and on Floors C and D four. In addition,
the product demonstration space has 40 ports for demonstration equipment. Multimode
62.5/125 碌m fiber is used as backbone cabling and UTP Cat 5e for horizontal runs.
Workstations on Floors C and D and in the product demonstration space should have faster
network connectivity than other users. Each floor has two telecommunications closets
because otherwise the horizontal runs would be too long.

What could be the best LAN Design for this scenario? (There are 250 employees
all)

Great information and thanks for the help really aprechiated .
I have just a few more questions .
I was looking to implement this lan using IP addrerssing how would I go abot that.Any Ideas on how to make the lan more resilient and foult tolerant.
Cheers

Blimey... Don't want much do you?

Seems like a fairly standard setup.

I would start with a 48port Gb layer 3 switch in each of the cabs on Floor A, B, C & D

I would also have either another beefy layer 3 switch (or Router) Depending on your connection to the outside world in one of the cabs on the ground floor with all of the switches fibered back to it; If you really wanted to go wild, you could put a backup layer 3 in the other ground floor cab for resilience - Also fibred and spanning-treed.

Then I would create VLANs for:
a) The connections in the Product Demonstration Space
b) The Ports of Floors C & D - Seperating Consulting & Development if possible.

This would give better performance than just having one big network.

If the speed still wasn't sufficient you could double up the network cards in the PCs on floors C,D & in the Demonstration Area and Channel bond them - This would probably mean an extra switch in each cabinet on those floors though.

Then you'd just sit back and wait for the smell of burning..

Should work fine though