Linux can be integrated with Windows on a Server/Client basis by using Samba (in Linux), but it does require a certain amount of Linux expertise to set it up.
Depending on what the company wishes to run by way of applications and if it is a "green field" set-up, it may be possible to offer a complete Linux solution.
Someone like SuSE (now owned by Novell), I'm sure would be pleased to have the opportunity to advise and could also offer a complete support package with the solution if required. Novell of course, have long been recognised as network specialists.
One way or the other, the server is just a vehicle for bringing together the desktops within the company and of course, in the case of Windows XP, each desktop requires it's own licence, which in some cases, can be a considerable expense. Add to that licences for MS Office and you're probably looking at costs of around £3000 for a ten user operation (without the server licence).
Food for thought!
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