That's a loaded question. Of course, you are worth every cent. But what you need to find out is what do similar positions pay for the job and location. That would give you an idea the base of what you salary should be:
View the salary ranges for different job types and in
different markets:
www.salary.com
U.S. Goverment wage statistics by occupation and region: http://stats.bls.go
Directory of salary surveys
Want something more definitive as per your industry and expertise? Order these individual salary surveys to get a better position on the salary you should negotiate:
Job survey listings by profession - U.S. Market:
www.erieri.com
Job survey listings by profession - International
Market: www.erieri.com
Job survey listings for Executive Levels: www.erieri.com