Most of the time when I play WoW is early in the morning. Sure, I've got the once weekly time set aside to hang with Souldat and his wife, but I've settled into a routine where I play before I have to get the kids up for school. Since I'm up really early to go work out, I slip in some WoW time between 5-7 AM.
When I was on Stormscale (Pacific Time Zone server), that early time was great for dailies. You could get some dailies done, and then the server time would hit the 3 AM reset (6 AM my time in EST) and you could do the dailies again. It was also ideal for exploring; the likelihood of running into a pack of 80's while checking out Elwynn Forest was remote, particularly during midweek.
Ironically enough, I found the same competition for mining resources during those wee hours as I did at other times. Three of us (two Horde, one Alliance) would be duking it out for the same titanium ore in Icecrown, and you got used to being jumped just when you thought the coast was clear.
If there was one drawback to the early morning solo time, it's that the players for random heroic 5-man runs were few and far between. It wasn't an issue when I was handling the regular solo quest work, but now that I'm soloing the instances in Outland and the 5-man quests in Icecrown, I need to work on my gear. That means badges and instance runs.
Switching to an Eastern Time Zone server has it's drawbacks for some solo work -such as the dailies- but it's been easier to use the LFG tool to pull in a few runs. The last time I tried the LFG tool on Stormscale at that time, after about 45 minutes I gave up. When I tried using it for the first time that early on Area 52 --I chose an Azjol-Nerub run rather than purely random for the speed factor (10-15 minutes if you do it quickly)-- I only waited about 12 minutes before I got in and was on my way.
The irony of getting some 5-man runs in this early in the morning is that the pure randomness of the tool is defeated by the lack of players. For example, today's first run (the Oculus) had not only the same two guys from the Exodar server I saw yesterday (including one well run Druid tank), but another repeat player from a separate server. After a relatively painless run through the Oculus which included the occasional joke about needing coffee, we stayed together for a second run, this time through Utgarde Keep.
I had to beg off after Utgarde, but the quality of the PuGs in the 5 AM slot had me impressed. Compared to the lunchtime fare, the early morning runs are more about getting in, getting it done, and getting out. (Yeah, I know, insert tasteless jokes here.) I had yesterday's Azjol-Nerub run take twice as long as usual because the three guildies in the group had decided to go for the Hadronox Denied achievement without telling the other two of us, and that fight included both the healer and one DPS dying and running back to get into the fight.
If I had to choose between the two, I'd go for the early morning runs. They feel less like kids on lunch break at college and more like parents squeezing in WoW time before getting ready for work. I can get 2 to 3 runs in fairly quickly, get some questing done in Outland, and then I'm ready to start the day.
(It's still amazing that Dalaran is never empty, even at 5 AM. Org is dead then, but Dal? No way. I wonder whether Blizzard is planning on trying to spread the Dalaran concentration out a bit in Cataclysm, but I have no idea how they'd do it.)