PowerShell, Web Requests, and Proxies

Somewhat better is the following, which handles auto-detected proxies as well:

$proxy = [System.Net.WebRequest]::GetSystemWebProxy()
$proxy.Credentials = [System.Net.CredentialCache]::DefaultCredentials

$wc = new-object system.net.WebClient
$wc.proxy = $proxy
$webpage = $wc.DownloadData($url)

(edit) Further to the above, this definition appears to work fine for me, too:

function Get-Webclient {
    $wc = New-Object Net.WebClient
    $wc.UseDefaultCredentials = $true
    $wc.Proxy.Credentials = $wc.Credentials
    $wc
}