For multiplayer, Financial is indeed powerful and hard to pass up.
The cottage economy is the most straightforward way to play (vs a specialist economy) - and unless we have a real expert on running a specialist economy on our team, I'd strongly advise the monarch to pursue a cottage economy.
Now - just because we're going to run a CE - doesn't mean we
have to be financial... it just helps.
As Slaze mentioned - Victoria is widely regarded as a top MP pick, and for good reason. If we don't try to get Victoria, I'll bet one of the other teams does. It's been a long time since I played a MP game with more than 4 teams where SOMEONE didn't pick Victoria.
That said - one of my personal favorites in MP games is Hannibal. Fin and Charismatic - he can get bigger/more productive cities in the early game (when happiness is the big issue) and he gets a nice little military bump with the lower XP advancement costs. I find it's a nice mix between domestic and militaristic advantages. If you can snag Stonehenge, it's seriously awesome. Downside is that while the Cothon is awesome - it's expensive and only really useful if you've got a map with lots of water and friends to trade with. The UU (Numidian Cavalry) can also be totally killer... but if you lack horses early on, you quickly lose the window of opportunity where the Numidian Cav's are good.
Another all-time favorite of mine is Darius. (Financial, Organized) - He's a late game powerhouse - but the incredibly awesome Immortal UU helps you survive the early game. It's really the middle where you risk getting dogpiled.
If we opt to NOT pick a financial Civ, it's hard to beat either of the Caesars - I just
love Praetorians. Julius is the better general gameplay pick (with organized) - but Augustus with his industrious trait can grab a bunch of the awesome early wonders without as much fear of getting wiped out for it (thank you, Praetorians) - and then multiply the usefulness of those wonders by churning out Great People (thank you +25% Great People from the Forums). I've also found you should never underestimate the value of the half-price forge. That's a huge boost for everything.
So yeah - those would be my top recommendations. They're not in any particular order.
Note: For any new members who are not familiar with it already, you really should go play around with the
Civ4 BTS Leader Picker application. Makes it easy to see all the trade-offs.