Oddly enough, the SPList object doesn’t have a URL property which gives you the server relative URL of the List.

So, here’s a code snippet to retrieve it.

private static string GetListURL(SPList theList, bool serverRelative)
{
	var listUrl = theList.DefaultViewUrl;
	if (theList is SPDocumentLibrary)
	{
		var idx = listUrl.IndexOf("Forms");
		listUrl = listUrl.Remove(idx);
		if (listUrl.EndsWith("/"))
			listUrl = listUrl.Remove(listUrl.LastIndexOf("/"));
	}
	else
	{
		var idx = listUrl.LastIndexOf("/");
		listUrl = listUrl.Remove(idx);
	}
	if (!serverRelative)
	{
		var serverUrl = theList.ParentWeb.Url;
		serverUrl = serverUrl.Substring(0, serverUrl.IndexOf("/", 7));
		listUrl = serverUrl + listUrl;
	}

	return listUrl;
}