I got to use my basilisks in a 10,000 point Tyranid vs. Imperium mega battle this past summer. From one table corner to the opposite one, it was still only 13 feet. Every turn I dropped a shell on the farthest opponent away, not because it was tactically sound (believe me, I had my own fish to fry), but because it was worth it to piss that one guy off that couldnt do a thing about it all game.
In the end, Imperium Won 7VPs to 6VPs because I took out the tyranid Heirophant Bio-Titan on the last turn with my Lascannons. I love the smell of fried ichor in the morning.