I am creating a WebTemplate based on BLANKINTERNET.
I know the BaseTemplateId you reference in your web template isnt really used to anything, but still as a best practice should refer to the template that resembles your onet.xml the most, amongst other reasons for later upgrade scenarios.
BaseTemplateId should refer to the webtemp*.xml ID. Since my site collection root template is based on BLANKINTERNET i have two choices as i see it: BLANKINTERNETCONTAINER (id=52) that really just is a dummy entry that uses a provisioning provider to create a hierarchy of sites or BLANKINTERNET (id=53) that does the "real" work.
So far I'm sticking with 53 but would like to hear peoples thought on this.
More info on WebTemplates? Read "Vesku"'s excellent primer here.