download the mod by Luvian and play any civ you want.

http://rtw.heavengames.com/cgi-bin/forums/display.cgi?action=ct&f=9,21,0,10

i would go with the julli or the scippi. the gauls arent that hard to conquer as the julii and when i was the scippi, carthage was practacaly destroyed by me, egypt, nubia and the spainish. but i would go with the julli first. its alot easier and the gailic armies just have their strength in high numbers and have really weak units in the beggining of the game.

I would say Scipii is the easiest, then probably the Julii then the Brutii. But its all about style. I dont like building "big" armies, so just tend to move elite forces around that garrison towns, as such i find taking all of Gaul quite challenging, since its wave after wave of barbarians which usually outnumber me 2-1 or more.
With carthage on the other hand, after about 3 set-peice battles, I ruled their entire faction and the wealth of the world was mine.

Conquering greece isn't that difficult, but its probably more challenging than the other two if your "new". After five minutes you can defeat a phalanx.. but your no longer new after that :P

I would say that the Brutii are fairly easy early on until you actually invade Greece. Then it gets really hard until you take Greece and Asia Minor. At that point your economy just explodes and you become wealthy out of your mind.

The Scipii are fairly hard in the beggining, but they become moderate after you consolidate Sicilia and use your fleets to consolidate the Mediterranian. Then you can take North Africa after some hard fighting with the Carthaginians and some easier fighting with the Numidians.

The Julii are kind of difficult early on if the Gauls hate you because it doesn't take much time for them to get some of their better units while it takes you a long time. After you start pumping out Principes and Triarii and later, Legionary Cohorts, they're utterly screwed.

I played the Julii first and found it to be a good introduction to R:TW (although I'm a Medieval veteran). The Gauls' low-tech units break themselves against a well-organised line, and although they have superior archers to the Romans they hardly ever field them. An smallish army of Hastati with wardogs and Equites, organised well, can easily beat any medium-level Gaul army.

I like the Scipii better than the Julii because of better temples.The awesome temples of Vulcan that give them military upgrades and the temples of Neptune give them killer ships to control the seas with.

I love the brutii... the beginning is hard, but once you're done with the greeks and macedonians and you hold Asia minor, nothing can stand in your way.