Anything from an 6to4 address typically gets routed to 192.88.99.1 (IPv4, protocol number 41), unless IPv6 is configured in a really weird way.
Since your ISP does not have their own router with the 192.88.99.1 anycast address, *all* IPv6 traffic goes through one of their peers who advertises their route to 192.88.99.1.
The actual destination IPv6 address doesn't matter (unless the destination is also a 6to4 address, in which case, the traffic is typically routed directly to the encoded IPv4 address instead of 192.88.99.1).

That's because you are using an IPv6 address in the 6to4 address space, not a native IPv6 address.
And according to trace, your ISP doesn't have their own 6to4 router deployed, so the traffic gets sent to whoever announces the shortest route to 192.88.99.1 route via BGP.
(192.88.99.1 is a special IP which means 'any 6to4 router')

Yes, in fact, stateless autoconfiguration implies using at least a /80 prefix.
And I don't see why ISPs would want needless complexity of keeping track of every device in a household.

Are you sure these are not 6to4 addresses (2002:<your_v4_IP>::xxx)?
By default, Vista and Win7 will automatically allocate a 6to4 address for each non-private IPv4 address configured on the computer.
(since you mentioned ipconfig and not ifconfig, I assume you are using Windows)

This will only work if the drive doesn't do background 'scrubbing' to improve future write performance.
Or, even if the drive didn't erase physical Flash cells yet, it could already mangle the mapping between the logical and physical blocks.
In fact, I have a cheap CompactFlash card that does exactly that when you yank power from it while writing - the drive appears completely scrambled (with blocks reordered) when you restore power to it.

Something as simple as deleting the wrong partition becomes an irreversible operation if you do it using a tool that supports TRIM on TRIM-enabled hardware.
Even if you restore the partition table from a backup, you will likely suffer silent file system corruption, which may even not be apparent until it's too late.
If TRIM support is actually implemented on the device, the device is free to 'lose' data on TRIMmed blocks until they are written at least once.

Even if you go IPv6, you still need to provide at least a NAT-ed IPv4 address or a transparent HTTP/DNS proxy.
And the 'transparent proxy' solution will break everything except HTTP, most notably, HTTPS.
You can communicate with IPv6 hosts from an IPv4 address (via 6to4 encapsulation).
But you cannot communicate with IPv4-only hosts using an IPv6 address without a proxy.

By the way, does Linux have disk I/O prioritization like Vista does, and is it enabled by default?
For example, Vista indexing service also generates a LOT of disk I/O, but it runs with 'background' I/O priority, and the impact on the disk response time is not nearly as significant as running an add-on indexing service for WinXP.
Most add-on indexing services for XP (Google, Windows Desktop Search) will stop indexing if the user is using the keyboard/mouse for exactly that reason (no way to prioritize I/O).