Hi there.., Atleast following quality should be there with an asp.net programmer.
1) Must know what is web technology in every content starting from cross-browser to web-Services and so forth.
2)Code management -> should have knowledge of how to code the program...? for redundent code one should always create method.
3) consistency -> Always have a signature for your work I mean to say to achieve same task use same approach.
4)loose Coupling -> Your block of code should be very less depended on other block. so at the time of changing one code piece should not make compelsory for you to change other.
5) Controls. -> You should have knowledge of weight of controls. As far as possible you should use lighter control., it quicks the websites performance. Whatever work can be done by Repeater for that u should avoid GridView.
6)Testing; -> Irrespective to tester people in your organization you should have not great but good enough skill to test your part of work. Never do Testing as Programmer but as Hacker.
7)Database -> You should have knowledge of database or query optimization.., You should not query more data than requirement.
8)Debugging -> As its a greate feature provided by visual Studio ... have more benifit to quickely fix your problem.
9) Design -> Every organation has special Desiger people who care look and feel of the page.., but you must have good knowledge of the Css And Html.