As I type this I am awaiting my S5 in the mail, I am a little concerned about getting virus?
The virus thing has been greatly exaggerated by the media. Your actual chances of getting a virus without disabling your security are very close to zero.
F-Secure: Android accounted for 97% of all mobile malware in 2013, but only 0.1% of those were on Google Play
At the very bottom of the list was Google Play itself, with the lowest percentage of malware in the gathered samples: 0.1 percent. F-Secure also noted that “the Play Store is most likely to promptly remove nefarious applications, so malware encountered there tends to have a short shelf life.”
Android Accounted for 97% of All Mobile Malware in 2013
So your chances of getting a virus from the Google Play store are 1/10th of 1%. I have been using Android devices since 2009 and have never gotten a virus, nor have any of the dozens of Android users I have known in real life.
Are all apps in google play safe like in apples app store?
If you mean are they actively scanned, then yes, they are. The few that make it through are quickly removed by Google.
And should I install anti virus? Are all widgets safe?
Widgets are definitely safe. IMO, an anti-virus app is overkill as long as you are not disabling security (and security is on by default). It would be like installing a lightning rod on your car...yeah it might make you safer from lightning strikes, but your real chances of getting your car struck by lightning are remote.
Security, which is on by default, will prevent you from installing anything that does not come from the play store. You have to deliberately turn it off to be able to install non-Play Store apps. When people say "unknown source", they are talking about disabling your security to install a non-Play store app.
That being said, I have disabled security lots of times to install "unknown source" apps over the years and still have never gotten a virus.