Good grief, there's going to be a Favorite X-Type thread for every sodding type, now, isn't there? <<;
Ah well. In no particular order, again...
Lapras
It's an adorable plesiosaurid with a shell that lives in cetacean-like pods and communicates by pseudo-whalesong - and not only that, but it's also fairly usable - I'm rather enjoying the diversity of moves Lapras can run around with. I am
quite fond of the things, yes indeed. Lapras is another one of those iconic creatures - it's been around since Gen 1, available in virtually every generation except 3 (unless you count FR/LG), made multiple appearances in both the Anime and Origins as one of the protagonist's team members (I've always been rather confused at the anime's tendency to associate them with more tropical climes, though. Ah well, stranger things have happened before) - and though I highly doubt it will, I'm kind of hoping the thing will get a Mega Evolution at some point... Probably wishful thinking, but Mega Lapras would be amazing.
Abomasnow
It may be my bias towards grass types, but I have a bit of an appreciation for the fuzzy conifer yeti. I'm rather fond of Grass/Ice as a concept (though it rarely ever ends up being useful. Fire-types and all, le sigh) and the design, while rather WTF at first grew on me once I drew it in a more creature-y manner. I admit though - I've never actually gotten the chance to train one of the things. They've always been too stupidly late game for me. Someday I should probably pokesav myself a team of stuff I always wanted to train and never got around to and actually give it a shot...
Mamoswine
Another case of derp in official art but utterly awesome in my head, there's a lot to be said for some kind of bizarre primeval Überpig incorporating elements of glacial age wooly megafauna (fun fact: the word 'Mammoth' derives from Russian, meaning 'Earth Horn' - reasonable considering the thing were found buried underground and under ice - which makes it even more appropriate for Mamoswine). Plus, with that attack stat, HP and defense... The thing's a monster. Really.
Walrein
While I definitely prefer Lapras as far as Water/Ice goes, I always felt the Spheal line was the superior pinniped to the Seel line - and besides, look at this thing. IT'S A GOD DAMN WALRUS. That's all there is to say about it. Walruses are badass.
Honorable mentions:
Sneasel/Weavile: I've always liked Sneasel, though something seriously bothered me about that asymmetrical design - an issue that Weavile fixed (albeit in the process it gave the thing a fan of hair that
Londo Mollari would be proud of). The things are pretty damn powerful as well - but I don't think I ever really trained one, now that you mention it.
Jynx: Okay, so they're incredibly silly-looking official-art-ways - but I've always thought of them as some kind of terrifying snow banshees... and as it turns out they're literally based on the
Yama-uba of Japanese Mythology and assorted portrayals of it in Noh theater, so... not that far off, I guess! Incidentally, I used one in SoulSilver once and holy shit, the things are monsters. xD
Glalie: In the immortal words of a certain Katie,
DEMONFLOATINGHEAD! The sodding thing cracks me up, but its description/lore paint a much less amusing image for the thing - basically, it's not something you'd like to meet in a dark alley unless you're packing a BFG9000. I can appreciate it, but it's not a favorite.
Froslass: Froslass' design confused me for a while, until I realized that much like her counterpart, Froslass too is a DEMONFLOATINGHEAD - the entire body is concentrated in the head (that's why those hand-ears!) and the 'body' is a hollow bell-shaped projection - like a tail, or a mantle of some sort. That made me appreciate it a bit more. Stats-ways it also seems pretty nice - but again, not a species I ever actually trained.
Articuno: Actually, Articuno is one of my absolute favorite Ice-types, but I didn't include it in the list because it's a legendary and legendaries do not really count. Not only it is utterly gorgeous, but I'm also fond of the mythology around it - its connection to the weather as well as its tendency to appear before those lost in frozen mountains. The legends vary and Articuno has been portrayed in assorted works as either leading people out of danger or serving as a final 'kiss of death' to those completely doomed, "saving" them in a different, darker way. Just another lovely bit of Pokémon mythology. ^^