I may be utterly missing the mark here, but I've tended to see the Ρωμιός as having a rather uncomplimentary meaning - with the idea of a person who has ideas above himself. As such, I've tended to avoid using it. However, that may be down to the texts I've read in which that word has been used.
I would regard a philhellene as someone with a passion for Greece and its' culture and people - ancient or modern.
S.
Έτσι είναι η ζωή!
I think 'philhellene' has now shifted its meaning far more towards a passion for modern Greece, and can be taken as the equivalent of terms like 'anglophile' and 'francophile'. I think the word has always implied a passion for contemporary Greece, but originally that passion was fuelled mainly by highly romantic ideas of the Classical past. As the Hellenic Republic has forged its new identity since emerging from Ottoman rule, so philhellinism has shifted its focus away from the classical and ancient periods.
But how far can you separate the love of today's Greece from the romanticised love of the classical and ancient periods? Even if you walk around Athens and somehow manage to not notice the Akropolis still dominating the city, you can't avoid Poseidon Avenue, Athina Street, Homer Street etc etc. Nor can you miss all the archaeological remains on display at almost every metro station. I don't think it would be possible to love modern Greece without being aware of - and in love with...and proud of - its ancient past.
Anyway, I'm a philhellene and proud of it! I'm leaving London in less than 3 weeks, and moving to Athens to work as a Greek-to-English translator.
Dave