Ahh, I couldn't agree with you more about.. er, everything. P: Going into details about it would end up with me repeating everything you just said, so eh.

Spoilery: Exactly, the plot of the two episodes was great and having a future companion was a pretty cool idea as well. It was just the romantic twist that completely ruined it.
I think that's probably one of the reasons I love Donna so much, she's the only companion in the new series that hasn't fallen head over heels for the Doctor. Doctor Who really doesn't need romance and in fact, that was one of the things that I loved about the show originally, that it didn't seem to be too focused on romance. It was just action and adventure and fun.
Anyway, the Doctor can't fall in love because it would absolutely break him. As he himself said, he has to go through life seeing everyone he loves wither away and die, which is why he can't get too emotionally attached. He did it with Rose and his character really shouldn't be stupid enough to go and do it again.

Okay, done ranting. Hee, my friend who introduced me to the series came to London for a weekend visit yesterday and I took him to Earl's Court - didn't tell him why we were there and then told him to close his eyes when we got out of the station and led him to the Police Public Call Box. The reaction was pure gold.
Then we hugged it. xD