Okay... here goes...
For travel on land: I'd want at least one Pokémon for travelling purposes on land. Obvious choice would be Rapidash since I love Fire-types, although I'd like a Zebstrika too.
For travel on water: Again, would be useful. Ones I'd like are Lapras, Gyarados, Milotic or Samurott.
For flying: I would love[/u] to be able to fly! For that, I think I'd almost always choose a Charizard or Tropius. But some other ones I'd like include Salamence, Dragonite, Aerodactyl or Fearow.
For protection: In case things go wrong, I'd want something that could fight my corner! Probably a fighting type, I think I might choose Throh or Lucario. Although Machamp, Hitmonchan, Hitmonlee, Infernape, or Scrafty would do nicely too. Also, since Fighting-types are strong, I guess they'd be useful for heavy-lifting around the house, pushing the car if it wouldn't start etc. I'd also like a Growlithe/Arcanine for a guard dog, like someone else said on the first page.
Electric-type: I think I'd like a good Electric-type for charging stuff and generally impressing people (I think Electric-types are the most impressive looks-wise), and for that, I'd choose Ampharos or Zebstrika.
For a pet: I'd love to keep a Lillipup just for a cute pet :) I love dogs, so it's an obvious choice.
Eeveelution: I'd also like an Eeveelution. I don't know why really, I just would. One that I didn't already have a type of (if that makes sense)... I think it'd be Umbreon or Leafeon... Umbreon looks cool (and I can see that being a good guard Pokémon too), and Leafeon 'cause, well, I haven't named any Grass-types so far.
Ditto: Surely I needn't explain this one? :P
That's all I can think of for now...