Asnchronous Vs. Multithreaded application

Question

Hi , I am developing a Client-Server application , I have done some research and found there are three ways to handle multiple client requests. 1. To use old style multithreaded server 2. To use .NET threadPoll worker threads 3. Asynchronous Socket programing But I am confused that which appproch I shld go.... ? My clients will run and provide all local info to main application ( Server ) so its the clients who actually will provide info to server/the Main Monitoring application(server) . Any guidence please to which approch I shd go ? Clients will be less than 50 ... and the Info they will provide on based on Events generated by Server. Thanks in advance.