Suggesting a default filename

I like to leave log files where people can find them.  Typically this is on their desktop, or in the same folder where the script ran from.  I wrote the following bit of code which creates a date based report file and offers it as a default.  It is pretty straightforward, but I did not know about the date formatting bit until I did this.

#Define default log
$lfd ="$env:userProfileDesktop"+$(Get-Date).ToString("yyyyMMdd_HHmm")+"_Report.txt"

#prompt for logfile unless specfied with -Logfile parameter (not shown)
if (!$LogFile){
    $logfile = Read-Host "Enter path to text log file, or ENTER for default,`n$lfd"
}

#use default log if not specified
if ($LogFile.Length -eq 0) {$LogFile = $lfd}

Write-Host $LogFile