I know we like to grumble at bad suppliers, so can I just offer some praise to a supplier who I believe has provided service above and beyond the call of duty:http://www.byvac.co.uk/
I bought an LCD display and VT100 serial controller from him, and was having problems. He let me send it back, with my Arduino, tested it and got it all working, and even wrote up the project as a tutorial for others. The Arduino in the write-up is mine ! Total cost: £1.72 for me to post it back to him.
The write-up is here: http://www.asi.byvac.com/ard_home.php
Superb. Highly recommended.