As above, it depends what you want. I look for a sharp drive - i live amongst a few great tight B-Roads and i like to drive at 7/10ths - at this pace the Golf is refined, balanced and i feel it really flows down the road. (If you have the manual, the pedals are perfectly positioned for heel-n-toe changes) - It has enough power in my opinion - and im not interested in top speed, anyone can be a straight line hero...
The Golf does everything brilliantly, i've heard the Focus has its flaws (can't get the drivers seat low enough) and the Astra is brutal with its torque steer (i do think it looks brilliant though)
When i was buying my car, i considered the usual options (Renaultsport Megane F1 230 is a cracker too) but i'm certain i made the right choice.
Simple remap will take it over 250bhp and can go undetected by garages, therefore is there any need to tell insurance companies? In this tune it will dust the others and also the heavier 4 wheel drive Golf R32.
Mine is standard and for now, its perfectly quick enough for me.