I wouldn't expect any Atheist, Humanist, or Materialist to believe in an afterlife, but for others that might be less committed to a naturalistic view, you really should consider the evidence.
Even if one doesn't subscribe to any of the various religions teaching mankind's presence of an eternal soul, it's hard to ignore all of the testimonies affirming this. There's been several books written on the topic of life after death, with thousands of interviews conducted on subjects having biological near death experiences. Many of these accounts have been at least partially verified from doctors' details, making it highly unlikely, if not impossible, for all of them to be dismissed as folly.
YouTube has several interesting NDE accounts that I've just begun to watch and assess. Following, is the best I've found yet from an expert in the field who has authored an excellent book on the subject. You know, denying one's Creator or soul won't negate the reality, and so far the Christian perspective holds up true to the evidence for this reality, be it scientific empirical evidence for the creation, prophetic evidence for the Bible's authority, or NDE testimony evidence for the accounts of meeting Jesus in Heaven. Here's a 45 minute sermon on the subject for anyone wanting some insight on what lies ahead after our time here.