My favorite Port Wine is Ferreirinha, don't know if I told you. Very smooth.
By complete coincidence, I'm going to see Sporting-Porto today, funny thing you mention it xD
Well, in a BIG game (any combination between Porto, Benfica, Sporting and sometimes Braga) it's pretty much impossible to get tickets, they are reserved for club "sócios". Any other game (even involving one of the mentioned teams) it's fine as the stadiums never fill up (tickets are expensive when wages are as low as they are here) so you can just get to the stadium on match-day and buy your tickets on the spot.
The best match to enjoy and have a good time is the Taça de Portugal final. Tickets aren't expensive and you can easily see a BIG match as the tickets are sold to general public. But this happens in May.
You can buy tickets online easily as well, but I've never done so.. I just show up and get them on the spot.
Porto's stadium is the best :D I also like Braga's, and I'll hit you up with my opinion on Sporting's Alvalade after todays game