*ahem* as the only person here who has actually been able to compare and contrast Spanish, Italian, French, and Portuguese wines (because let's be honest at moat you have drunk some Chilean or Australian knockoff..)
Red wine: I'd say Spanish and Italian red wines are mostly equivalent. A friend of mine who was an enologist told me back in the day that in order to get good wine you need to grow the grapes in poor, dry soil. Winemaking regions in both countries are similar so it kind of fits. Obviously if you go for cheap ones you're going to be drinking horrible shit, but you can get quality at reasonable prices. Vega Sicilia is supposed to be the best, but it's crazy expensive and I personally find Luis Cañas to be a pretty good red wine, and it costs you around 10-15. If you're so cheap as to consider that expensive, you can get a cune for 6 euro. If you think THAT is too much you can get a brick of Don Simon for 2 € but at this point you should consider buying bleach instead.
As for French red wines, eh, I lied, I dont recall actually trying those. Moving on..
Whites: supposedly Galician whites are really good (eg Albariño) but I dont really like white wine. Worth noting, however, Txakoli, the ancestral white wine of the Basque Country. Remember that bit from my friend? About good wine coming from poor, dry soil? Well, Euskadi is as wet as amywhere else in the Atlantic coast, it's very green and beautiful, and subsequently our wine is disgusting crap much like the stuff they try to brew in UK amd Germany. Avoid, even if you're only trying to get drunk. There are a number of regional drinks that will get you drunk faster and are marginally better.
Catalonian Cava vs Champagne: I'm sorry to say but champagne beats cava hands down. Moet Chandon is OK, but I favor Veuve Clicquot. Likewise I think Grande Dame is slightly better than Dom Perignon.
I warn you however much of the mistique of Champagne is the scarcity/novelty. Drink it too often and you'll see it as just a fizzly white wine. I know first hand.
Beer: I strongly favor Belgian beer/trappist beer, but I'm contractually obligated by the HSE to say that Guiness is just as good or else I'll be deported.
Portuguese Port: sweetish red wine. British people seem to like it, but they also drink wortesxershire sauce with water in planes, and according to the British consul the reason there are so many fatalities of British tourists is that
they are not used to balconies, and therefore they don't know how to use them safely.
Goes without saying, British people are not very used to good red wine either, so take their endorsement of port with a pinch of salt.
Port is really good as a base for sauces though