Been there done that, tried my best to clean up but every now and then you would find another "dropping" - the reaction I had was exactly the same as when you are wandering down the street and suddenly step in a dog dropping, same sort of revulsion and disgust at the filthy mess you just blundered into and now have to clean up.
Actually, if you are running exchange 2008 or later then you have to use powershell - the wmi hooks for vbscript just don't exist for later versions of exchange. You can get powershell for XP but you have to be on SP3.
Powershell does have its quirks though, the one that particularly catches me is trying to reference component of an object in an argument list. Doing a GUI is an exercise in patience. If you have done some perl programming then you should be reasonably comfortable with Powershell.
You could try using pkgsrc (http://www.pkgsrc.org/) on opensolaris for third party applications. There are a lot of packages for opensolaris already but I think that pkgsrc beats them. Alternatively, you could try your hand at sourcejuicer and feed the apps you want into the opensolaris pool.