> Hi, I am new to modular but I grew up from the Arp era.

Welcome!

> How can I calculate the amount of space a system will need

Eurorack modules are all measured in HP. I believe they're all an even number too. There are a few online tools you can use to try out new configurations and see how they'd look. Check out http://www.modularplanner.co.uk/ and http://www.modulargrid.net/ for two examples.

> I welcome case suggestions.
>
> The system would have to fit into a home office.
>
> Are the Doepfer cases a little expensive or are they good value

Personally I get the Doepfer version of anything I can (cases, any given type of module), but it's a very personal thing. You can get some very fancy looking ones from http://www.goike.com/ and other individual makers.

> Are there any cases that a a little more like furniture on the out side

You could always get the rackmountable G6 case, and a desk with a built-in rack..

> Are there any plans I can down load
>
> Thanks for your suggestions

Definitely check out http://www.doepfer.de/a100_cases_e.htm to see the cases available from Doepfer, and http://www.modulargrid.net/ for ideas on how to fill it. :)

All the best,
Zoë.