NEC has a system up on their site that claims to be a complete productivity solution in a package so thin (1.1") and so light (1.7lb.) that it can go with you practically anywhere. I think this sounds like a nice option. I took a look at it and it seems rather practical for use in some situations.
Used by a mobile professional, this would really give you what you need. 24MB RAM with 32 MB ROM, Handheld PC with Pocket versions of Microsoft Word, Excel, PowerPoint, Access, Internet Explorer and Outlook installed. It also has a 168 MHz MIPS processor to supply the speed you need. You get a stylus, AC Adapter, VGA cable, serial cable, RJ-11 telephone cable, rechargeable lithium-ion battery, Microsoft ActiveSync CD and user guide with this model.
Sounds very similar to an IPAQ that I once owned and I used it all the time for keeping contacts, calendar dates and basic things. If I had set it up to use the internet and I was able to further use it to access all the programs listed above, I think I would have taken it with me just anywhere.
Take a look on the NEC site and consider this as an option if you're wanting to go mobile.