I would go with switches, you can even get unmanaged ones if you're not plannig to grow to more than 30 (if you will - better get the managed ones that you can create V-Lans in the future)

Pros: (for a network of less than 50 Computers)

100Mbit Full duplex, No more collisons.

if you get a managed one :

Remote management of Ports (error viewing, connect/disconnect) Grouping (VLAN ?) etc...

I wouldn't use one switch and than connect the rest of the computers to hubs... that kinda beats the purpose.

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Computers do exactly as you tell them - not what you want them to do ...