Warhammer 40K Tactics

[Wraith]

1. What's the best way to use a Basilisk in a game?
2. Which Heavy weapons are the most cost effective? I'm making HB, Mortar, and ML squads, but the Lascannons are kind of expensive, and Autocannons I don't know enough about.
3. Should I use the Autocannons/Lascannons to equip Sentinels instead of making heavy weapon teams?

1. Sit it in the tightest corner of your deployment area as you can - preferably on the very corner of the table so there's oblivion on 3 of it's 4 sides. It's open topped and has relatively weak armour, so you do NOT want things to be able to shoot at it's side or (god forbid) rear for any reason.

With the range of it's cannon, you can hit anything on the table, even in Apocalypse games. Pick a target and nuke it. Rinse and repeat.
A friend of mine has just suggested using a 'shield' of conscripts in the FRONT side of the Basilisk - that way it can't be shot at from the rear or sides, and the front gets a 4+ cover save by sacrificing extremely cheap and useless points. Also means it can't be charged in close combat, as your opponent has to kill the conscripts first before they can come into contact - an extra turn of shooting before it gets ripped apart!

2: I personally prefer autocannons as a general-use armament, as they're reasonably good against most enemies for a middle-range cost, but don't let that stop you changing them if you're facing different enemies. The lascannons will be a very good investment if you suspect that there are Monoliths or Wraithlord prowling around your next battle.

3: Again, depends on who you're fighting.
Sentinels are good for taking the fight to static armies (Shooty-Eldar, Shooty Marines, usually Tau) thanks to their Scouting ability, but against mobile ones (Tyranids, Dark Eldar) there's not really any need to get so close, so soon.
I would recommend taking a few of both if possible, so that you can play with them and decide which you LIKE to use the most, as that is usually going to be the deciding factor unless you need an emergency sideboard for fighting a particular enemy.

on a different subject it may seem illogical to shoot at necron destroyers but it can be more efficient then shooting at warriors if you wipe them all out. Unless fo course your friend has a tomb spyder or other destroyers nearby.

On the contrary, it's a very good idea. Destroyers are fast moving, so killing them stops the Necrons from getting into CC with you and therefore preventing you from shooting at them, so blowing them away in the first turn gives you the next 1 or even 2 turns to leisurekly snipe at the rest of the enemy.
And then you've got the whole Necron/Phase Out thing to boot. I struggle to find reasons as to why you SHOULDN'T shoot Destroyers first (the possible exception being the Tomb Spider, of course )