"Smith and Jones" wins out, easily. Great villain, great concept, it's excellently paced and is consistently entertaining.
"Rose" is definitely the second-best. As mentioned above, it has its bad bits like the belching trash can, but as the introduction to the entire new series, it works incredibly well. "Run!" is easily the best way to convey the chaos to the viewer.
"New Earth" is pretty weak, especially because of the "Oh, if I push a few buttons here, everyone's cured -- Yay!" conclusion. It's also the start of the silly Tenth Doctor / Rose giggling schoolkids romance, which drives me absolutely nuts. But I always dug Cassandra, and I'm a sucker for the appearance of the Face of Boe. The ending is incredibly poignant, as well. So it largely goes down as passable fluff.
"Partners in Crime" has a few entertaining bits, but the "almost missed 'em" aspect goes on entirely too long for the first while, and Murray Gold is at his absolute worst: The uppity-boppity, hippity-hoppity music which would be better off in Matchstick Men does not fucking stop. There's not a whole lot to like in this one, really.