When I am looking for papers, I use Google Scholar. Forget about PubMed or ISI Web of Knowledge, everything archived in there is by definition also present in Google Scholar. (The one issue I have with the Google algorithm is that the number of times papers are cited is taken into account and relevance and fame do not necessarily correlate.) A new feature is Google Citation, where after entering your name and field of research, your papers are automatically listed, citations are tallied and h-factor (x papers cited x or more times) is calculated. Although citation metrics are far from perfect and could be improved, it is quite a handy tool.