As an Imperial Guard player I have an overwhelming urge to drop as many massively armored titans of destruction onto the table as possible at any given time. Leman Russes of all shapes and sizes rolling where they choose, Basilisks and other artillery not letting anything stay behind cover and of course the utter and complete Goddess of Sex, the Baneblade!
I think if my wife knew how much I really like that tank she might force it out of my house.....
Anyways, I'm excited about Spearhead. From what it looks like, and the June White Dwarf is going to expand on this, it looks like an expansion that puts all your vehicles on the table. According to the Games-workshop.com blurb you play it lengthwise on the table so you have longer ranges and larger weapons to deal with.
On top of that, new tanks! I'm really liking the differant missile tanks like the new Manticore and Deathstrike launchers but I can't see a place for them in my army other than as a cool looking vehicle. I'm really more of a direct assault tanker since I've never had much luck with artillery. I think it's because I expect them to actually kill stuff when really they should be used as an area/cover denial weapon. I'll have to slip some pieces into my next army and try it again.