What he said.
I think Clarkson coined the 'All Cars to All Men' phrase and, like him or loathe him, I think it best describes the Mk5 GTI. Its not a sportscar, but its not an average hatchback, its not that expensive to run but not particularly cheap either. It looks great, its not not mega quick but quick enough for an average petrol head, you can use it like a normal car, you could take it to a trackday (within reason), great build quality etc etc. Back in the 70s this was effectively what the Mk1 did and the Mk2 (some would say) improved upon later on. The Mk3 and Mk4 IMO lost this overall balance.
I'm no stranger to modifying cars, but for now I'm happy with the all-rounder my car is. If I wanted more power and comprimises for a particular style of driving, I'd have probably bought an M3. That said, I'd love to have a go in a Stage 1 Mk5 to feel the difference that lots have talked about and I wouldn't rule it out in future.
Ultimately people will have a preferred 'balance' of standard v mods and that diversity is what makes me enjoy using the forum.