Which DTD is better Transitional or Strict?

Is XHTML 1.0 Transitional an acceptable DTD standard to use rather than
XHTML 1.0 Strict! Especially if you are claiming to create totally
accessible web sites?  I realise there is more to accessibility than getting
the code correct but the W3C site says nothing about whether this DTD is
acceptable or not. 

The Web Content Accessibility Guidelines 1.0 only say that you should:

3.2 Create documents that validate to published formal grammars.  

XHTML 1.0 Transitional is a published formal grammar, correct? So does that
mean its ok and you can claim priority 2?

Does anyone have a definitive answer to this?

Regards,

Terry Dean