Rebuilding Network from ground up.

I just took a position as a Systems Administrator (Only IT Guy Basically) for a small company and have been tasked with making the network better.  I have looked it over and know that I will have to rebuild it from scratch.

Current Environment

20-30 users

50 – 100 devices

We have an IP range for Network A with users and servers, a second range for Network B that has users and equipment and then a third range for Network C that has phones on it.   

Idea for the new setup

I plan to replace the switches with all new ones and create a flat network for everything and as we grow or need I can start to break the network up.  I plan to use VLANs for this and not subnet but my boss wants me to look into subnetting in case we need to go that way in the future.   But for now I plan to get layer 2/layer 3+ switches to handle the VLANs as I understand this is a more common practice.   The only reason that we would need to VLAN is to separate some equipment we use off so it cannot be accessed by every computer on the network.  

Main Questions I have:

1.  I am trying to decide on which switches to go with for a small network that could grow very quick.  I am looking at Gig Switches, stackable, 48 port, POE, Layer 2/Layer 3+.  I have looked at these three so far.   Netgear GS752TSB Opens a new window, HP J9772A Opens a new window, Dell PowerConnect 6248P Opens a new window

2.  Am I correct in doing the flat network or should I look at subnetting?  My boss would like to use a Class A network so My though is to use 10.0.0.1-10.0.31.254 with a subnet of 255.255.224.0 as my scope so I can set like:

10.0.0.x-10.0.5.x = Static Range for Servers

10.0.6.x-10.0.11.x- Static Range for Network Equipment\Printers

10.0.12.x-10.0.17.x= Static Range for Shop Equipment

10.0.18.x-10.0.23.x= Static Range for Security Equipment

10.0.24.x-10.0.31.x= DHCP Range

Now I know that my NO means is the company big enough for this kind of network but I have had it suggested to do this so the Static Ranges are not just 1 range on top of each other and if I did have to grow a range past the 255 devices I could and they would still be “Grouped”  So thoughts on this are welcome.  

I will say that networking is by no means my strongest talent but I want to know how to set this up the best I can so thus I turn to you guys for guidance.  I look forward to everyone input and help.