Critizine.com

When going on holiday, it could be quite practical to have a travel guide of a certain country/region with you, but which of the guidebooks do you take? There's an abundance of different guide books, of which Lonely Planet is of course best known.

When you're travelling, do you take a guide book with you. or just some maps with directions? Do you have a favourite type of guide? And how do you choose the best guide for your trip?

My parents used to bring some typical Dutch guides with them, like the 'Capitool' guide books or the ones from ANWB (those books are not that great on practical info, more pics and random info than really usefull stuff), or buy one locally. My brother was more fond of the Lonely Planet guides and now we're also trying some of the 'Rough Guide' books.

Do you stick with one type, or do you sometimes switch?

Here are some of the sites:
http://www.lonelyplanet.com
http://www.roughguides.com
http://www.moon.com (Moon travel guides)

and a site were you can get them (sometimes) cheaper than the regular prices:
http://www.bookdepository.co.uk/

Individually asking can indeed be a good way to find your way somewhere, though that sometimes depends on your travel companions (some people seem to have a fear of going to people and ask for directions )
As you mention the maps... those are also quite crucial

I mostly feel sort of 'safer' if I have a guide book with me, especially if you, just to have the opportunity to check the book as often as you want .
As we noticed in NY, some guidebooks are more usefull as background reading before you go, whereas other guidebooks are more usefull (practical) during the trip itself.
For Prague I've got a rough guide again, and I'll see if it's practical enough , though the opinions of the usefulness are mixed.