I'm running census on trial account(s), so I don't need to worry about purging my local database or sending redundant info to Rollie. One of my reasons for doing this is that I really don't have the resources (time-duration/etc) to play on my live account (doing dungeon runs etc.) so until my local situation changes it doesn't make much sense to give Blizzard money just to cycle through realms while the add-on counts characters.
If I feel like playing a specific combo (race/class/realm), I'll select them first then check and recheck the most needed list/submissions pages and populate the account with about 20 characters. The only selection I make in the character creation screen is to make sure I have the right faction (either one of each or only the one that isn't getting census love. Which means that I end up with Blizzard provided random(?) class/sex.
Normally I name them Census{A/H}(class related name)
ex: CensusAmag, CensusHunter, CensusALoc
I try to remember to get my last day's run in then delete the characters from the account.. so I can reuse the names again if and when the realm census run numbers drop back down into the most wanted list again.
I'm using a Vista 64bit system and I've found that after I did a full reinstall I'm not getting the focus retained on the wow window if I tab to my browser... even if I elevate the process priority for wow. While I use to be able to place a character into the world and then switch to working my email or browsing the web.. now I can't if I want the census to actually run at any reasonable speed.
But since there is plenty of things to do that don't use the computer.. I can get lots of census runs done while working on other things.. I just listen for the end of run sound or failing that I check the computer every so often
or not
. When I have the computer on I typically get 3 or 4 census runs on the realms per day unless I'm actually using the computer for other purposes.
When I first start census runs on a realm/faction I typically have no clue what the population might really be so I spend a little time playing the character through the starting zone(s) {skipping anything the might bore me}. Once I know how long census runs will take.. I'll either say a) I'm having fun with this character so keep playing (larger pop realms) or b) run the character to the nearest inn to minimize the log off time and just ignore the character (quick census run realms). Playing a character that takes longer to log in and out then to do the census run isn't very fun or effective.
Which means after the first day or so on the account I ignore characters in Inns and play them if they out and about the world. Though Play is a rather loose interpretation of the actual events, I've been know to 'Play' a ghost character for more then one census cycle while it does/doesn't wander around looking for the corpse.
I upload my data either after a full cycle of all the realm/factions or whenever I know I'm going to be away from the process for an extended period of time. While I do use the Uniuploader program to send my data I do the uploads manually and not with the automation in the program.
Generally tab out and read forums, websites, or play on my other account 
