Just to share some findings on working with SharePoint features:

• The Elements.xml file that you include with your feature deployment cannot contain XML comments; if it does, you will encounter an error when you try to activate your feature using STSADM.exe.  Why?  Who knows.
• The <type/> element in the Elements.xml file, according to the schema documentation, can only occur once.  This seems to imply that you will need a different Elements.xml file to subscribe to each event type that you want to handle.
• And of course, Microsoft does not include the list of valid values (and if they do, it's not easy to find in the documentation).  Instead, I pulled the values using Reflector from the SPEventReceiverType enumeration.

The following is the enumeration listing:

public enum SPEventReceiverType {
    ContextEvent = 0x7ffe,
    EmailReceived = 0x4e20,
    FieldAdded = 0x2775,
    FieldAdding = 0x65,
    FieldDeleted = 0x2777,
    FieldDeleting = 0x67,
    FieldUpdated = 0x2776,
    FieldUpdating = 0x66,
    InvalidReceiver = -1,
    ItemAdded = 0x2711,
    ItemAdding = 1,
    ItemAttachmentAdded = 0x2717,
    ItemAttachmentAdding = 7,
    ItemAttachmentDeleted = 0x2718,
    ItemAttachmentDeleting = 8,
    ItemCheckedIn = 0x2714,
    ItemCheckedOut = 0x2715,
    ItemCheckingIn = 4,
    ItemCheckingOut = 5,
    ItemDeleted = 0x2713,
    ItemDeleting = 3,
    ItemFileConverted = 0x271a,
    ItemFileMoved = 0x2719,
    ItemFileMoving = 9,
    ItemUncheckedOut = 0x2716,
    ItemUncheckingOut = 6,
    ItemUpdated = 0x2712,
    ItemUpdating = 2,
    SiteDeleted = 0x27d9,
    SiteDeleting = 0xc9,
    WebDeleted = 0x27da,
    WebDeleting = 0xca,
    WebMoved = 0x27db,
    WebMoving = 0xcb
}

Of course, these values are in hexadecimal and for some reason, the <type/> element insists on the integer values.  So just be sure to convert the value to integer (try using Google for that).