My oppinion is that if you are only looking for a quality, then take Audi/BMW or sth like that. Maybe even Citroen DS4 which I think is of high quality car.
I wanted to like the DS4, and it has a really nice cabin, but it's nowhere near to the Giulietta in terms of technology (suspension, drivetrain, engines) or comfort. I was disappointed. It's also much more of a "crossover" style car than it looks in photos, which is another turn-off for me.
A3 should be off anyone's list until the new one comes along next year. The current A3 was never a good car IMO - overly hard with lifeless steering, and everything's an option on an already saucy base price. The new BMW 1 is good, but it's also very expensive: the entry 116i 120bhp is £20,000 where the equivalent Giulietta (1.4TB 120bhp) is only £17,000, with similar emissions/tax. Sure, it might be better, but is it nearly 20% better?
On the original post:
I am looking at the Giuilietta and was hoping for some general advice on the choice of engine (probably diesel), colour and essential options. Its either this or a rather bland Golf or A3.
If it's a choice between a Golf, A3, and Giulietta, then it's the Giulietta by a nose from the Golf. The VW is the safe option and its diesel is quieter at standstill than the Alfa's (when driving, there's no difference). Plus, if you buy a Golf, you won't have to explain why you bought one. But, and this is a big "but": the Giulietta is more fun, it's more comfortable (yes, really), and it has better performance.
Engines: If it's diesel you need, then don't discount the 1.6 - it's a fine engine, and pretty well priced too. It might be "only" 105 bhp, but it has a good healthy torque, and well delivered, so it picks up well. It's also quite capable of cruising at over 90mph without you noticing (luckily the cops weren't on the road that day!). The 2.0 is a little coarser, but also more powerful. The 140 bhp 2.0 sneaks in under the important 120g/km limit, but... so does the dual-clutch auto 170 bhp model. Both the 140 and 170 have the same torque, so there shouldn't be a huge difference in "real-world" driving performance. (I haven't tried the 140, though - it's not offered in Ireland).
My order is going to be for a 170CV 2.0 diesel with dual-clutch auto, unless the transmission turns out to be a complete dog when I drive it (This is very unlikely, based on initial reviews).
Colours - I absolutely love Etna Black: in low light it looks like deep, high-gloss black, but when it catches the sun, it flashes red. The darker of the metallic grey (Magnesio?) looks good too, especially with red leather interior.
Options - a lot the useful stuff is already standard, so you won't add many unless you want some luxury. I'm going for leather, and the electrically-adjustable seats (as my wife will also be driving the car), and staying with the standard 16" wheels because of the mountain roads between our house and my in-laws' place.