We don't have any of these sort of things, and use 'proper' office-style computer.
But I always think, for anything, have the largest screen you can, unless carrying around, being in a pocket etc, is an overriding consideration.
Apple products are always more expensive than similar things from other companies, but I don't know specific brands to advise. Some companies have free 'open source' software, but it may not be fully compatible with Apple or Windows.
Office for iPad may well be coming soon - see here.
Google Docs (Google Drive) is available on iPad, so that could be used for viewing some documents perhaps.
If you have to have full versions of Excel and Word then I feel you are best waiting to see what happens with regard to Microsoft releasing Office on touch devices.
Meanwhile, this help page may be worth a read about what capabilities iPhone Office365 is capable of doing.
Why do you want something to do home and work stuff on, could you not perhaps separate that out - get iPad for you to use, get work to provide you with a laptop or desktop for work stuff if they require you to use specific software.