Windows XP thoughts

So, as I mentioned in the desktop thread I'll probably buy a copy of XP Pro soon (I figure Home might be a bit too restricted, and Professional sounds better than home
).
Anyways, as I understand it you'll have to call MS and give them a 50-something number key and get a >40 number key back in case you change a lot of hardware, is this correct, and does anybody have any activation horror stories to share?
In case MS would cease their XP activation service in the future (or the activation process becomes too much of a hassle), are there good activation cracks that gets rid of this problem but doesn't bring any bad things with it (like your serial being blacklisted or whatever)?
TIA

Anyways, as I understand it you'll have to call MS and give them a 50-something number key and get a >40 number key back in case you change a lot of hardware, is this correct, and does anybody have any activation horror stories to share?
In case MS would cease their XP activation service in the future (or the activation process becomes too much of a hassle), are there good activation cracks that gets rid of this problem but doesn't bring any bad things with it (like your serial being blacklisted or whatever)?
TIA