Proper road maps are essential if you're driving or cycling. Quality European map publishers include Michelin (www.michelin.com), Freytag & Berndt (www.freytagberndt.com) and Kümmerly+Frey (www.kuemmerly-frey.ch).
As a rule, maps published by automobile associations (for example ACI in Italy or ELPA in Greece) are excellent, and are sometimes free if membership of your local association gives you reciprocal rights.
Tourist offices are a good source of free, basic maps.
Good maps are easy to find in bookshops throughout the region.