at home there's the overpowered desktop with about 300€ worth of hardware + 300€ worth of audio gear + 0€ worth of CRT displays (I feel CRT is easier on the eyes and easier for gaming..)
mouse + keyboard beat any laptop or PDA phone, ditto an actual pair of 80W speakers.
also that I can replace single pieces of dead hardware as they crap out is nice.
I use an actual notebook made of wood pulp (or what is the term for the simplest form, without a spiral)
I write it from one side for projects, procrastination etc. and from the other one with contacts, meetings, addresses etc.
I tried the netbook route before but while it had a crisp, vivid screen (first time I'd like a LCD, small size helps) it was unreadable in indirect sunlight, also the keyboard same as on eee PC 900 was unreliable.
the paper book is an order of magnitude lighter, thinner, reliable and I can carry it all the time in the backpack - I can still use it even in the event I go homeless or civilisation collapses.
other good tools are the yahoo webmail - both mails to self and text notes, ssh (i.e. ubiquitous access to text files, persistant IRC client, and file transfers!), anyterm (to log in to a text console from a browser, if one day I have to use a computer without ssh client or a locked down network), soon a home server will go online, and lastly a USB drive tied to my bicycle's key so I have it 24/7 with me and it's unlosable.
I believe I would get a PDA phone with keyboard if I had the need, though (as long as I can buy it not from a carrier and it concentrates on offering usb, audio jack, phone calls and a keyboard rather than pointless specs)