Nowadays I tend to prefer Hargreth's http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=1443 when I use a Balmora expansion mod. As much as I appreciate the work that went into Balmora Expansion it just increasingly seems like a bit much for my taste as time goes on. But I have to say, BE has a lot going for it, it has great features you won't find anywhere else. My advise is to load one mod up, COC to Balmora, walk around for awhile and get a feel for how the mod changes the place. Exit, load another mod, COC to Balmora, walk around and see how you like that one. Keep trying mods out until you think you've found one that feels most comfortable to you. That's what I do.
As far as expansion for other towns, here are some that I use:
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=1725 - Nemon
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=1908 - Loki the Grouch
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=2903 - Princess Stomper
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=3375 - Princess Stomper
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=3461 - Princess Stomper
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=390 - Lonnie
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=3084 - Lochnarus
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=1534 - Hoghead the Horrible
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=2615 by Max
http://planetelderscrolls.gamespy.com/View.php?view=Mods.Detail&id=2693 by Max