As is often the case, my PowerShell boundaries were expanded because of a question from a coworker. This week Laura had a document library that had over 7000 files and she needed to delete it. Unfortunately it had blown long past the large list throttling limit. When she tried to delete it in the interface she was greeted with this very unfriendly page:
There are a few ways to deal with that, but she asked for a PowerShell way and who was I to say no? She could have gone into Central Admin and tweaked the throttling settings. She could have also logged into the site collection as the farm account. SharePoint will let you delete it that way too. But she wanted PowerShell, so by god I gave her PowerShell.
But first, let’s reproduce the large list, using PowerShell of course. Use the following PowerShell to create a list and add column to it:
$web = Get-SPWeb http://sharepoint/sites/team
$lists = $web.Lists
$lists.add("Gordo","Mucho Grande", "GenericList")
$custom = $lists["Gordo"]
$custom.Fields.Add("Number","Text",0)
Substitute the URL for one on your farm. After the list is created, use the following PowerShell to create a few thousand items.
for ($i=1; $i -le 7010; $i++)
{
$item = $custom.items.add()
$item["Title"] = "Item Title" + $i
$item["Number"] = "42"
$item.update()
}
Now that you have the list, log in as a site collection administrator that is NOT the farm account and try to delete the list. You should get the same error above. PowerShell to the rescue! I hope you’re sitting down, here’s how to delete that pesky large list.
$web = Get-SPWeb http://sharepoint/sites/team
$custom = $web.lists["Gordo"]
$custom.Delete()
Blammo! Large list de-leted! You can download all the glorious PowerShell here.
Thanks to Laura for expanding my horizons. 
tk