Hi,
avast doesn't detect Msblast=blaster=poza=lovsan yet, but i guess there'll be an update soon.
to check for individual viruses, look in the virus database.. (i get 23000+ detcted viruses, try "*")
This number is irrelevant anyway, as Avast detects lots of viruses of the same family by generic/heuristics, whereas Norton lists every slightly different variant as a new detection.
I don't think Norton is really better than Avast in detection (apart from Norton being a ressource-eater);
if you want top-of-the-line, use Kaspersky or AVK
to find out, how Avast names the viruses you mention, search the databases of McAfee, TrendMicro or VGREP (the latter is usually behind several days and lists only the more important viruses-> in-the-wild):
http://www.virusbtn.com/resources/vgrep/index.xmlP.S.: you'll probably never encounter Malware which Norton lists with threat-severity of "1", i.e. all of the above except blaster.