If you're asking for a no-ad host, that's already saying, "I want the best host out of the cr*ppiest hosts out there." You can't expect any no-ad host to be good. In terms of features,
http://www.portland.co.uk/, but everyone knows the quality of their free hosting. In terms of reliability,
http://www.liquid2k.com/ is BY FAR the best. Host.sk plain sucks in reliability, but it has quite an impressive list of features. Portland still has more though, but nothing can come close to the unlimited space/transfer that host.sk offers.
Overall, these would be my ratings:
Liquid2k 8/10 - no FTP, no scripting languages, very reliable
Host.sk 4/10 - unlimited space + transfer, PHP/MySQL, unreliable, slow
Portland 2/10 - 15 MB + 100 MB transfer, PHP/MYSQL/CGI (they have ASP too, I think), totally unreliable, slow, poor security