Basic imperial ships are usually a third cheaper in points to rebels. Not including z95.

Get something you like.

Maybe another xwing. There are extra pilots in the expansion that are well worth getting.

It might be worth going on afewmanuevers as that has a full expansion list so you can compare costs before buying

A YT-1300 and a Firespray

What about a y wing, I don't know the ships at all so I have nothing to go on.

The closest equivalent to the Tie Advance on the rebel side is probably the E-Wing, at least in terms of similar roles in a typical squad, though I think most would agree that these two ships really don't compare, the E-wing is clearly superior and that is rightfully measured in points by the E-Wing beinging more expensive.

Right now though with a core set (2 Tie's and an X Wing) plus a Tie Bomber and B-Wing the collection is a bit offset, it clearly favors the Rebels. The Tie Bomber is really not a point (or ability) equivalent to the B Wing, in fact while you can draw comparisons in terms of points and roles between the two factions, in practice the two factions really are different and the ships don't really have true mirrored role ships or point values. You really have to trust in the point system, its well balanced, but typically the Imperials will have more ships for their points.

I suggest another Core set, plus a Tie Fighter expansion and an X-Wing expansion. That will give you 3 more Tie Fighters and 2 more X-Wings. That will already balance the playing field a bit. I would get a couple of interceptors before the Tie Advanced. Then perhaps a couple of Z95's or A-Wings for selection choices for the Rebels to help fill out the list.

Home games usually don't push competative play but like you I want to have a balanced collection at home so me and my friends can form squads and play. That said, the core set is clearly not enough and you can't view the balance of the game as "buy one ship for rebels and buy one for the Imperials". You need to have more ships for the Imperials to balance out the points.

If you don't what happens (and this happened to me) is that the rebel player is constantly squeezing points, while the Imperial play is constantly stretching. Another words, the Rebel player has to take cheaper equipment or lower priced ships to field everything, while to be point equivalent the Imperial player has to get the most expensive ships and buy the most expensive equipment to reach the points for the game.

You want to eliminate that push and pull by having more ships available.

A good start for any collection is 2 core sets, 1 x-wing expansion and 1 Tie Expansion but even that pulls and pushes a bit too much in my opinion.

Get the TIE Advanced if you want to (Vader is fun), but realize that currently it's out of favor. FFG did promise that something would give us reason to hope for its return, but right now it's a tough ship to be competitive with.

But, maybe it's just too soon for you to worry about competitiveness. Right now what you want to have is fun.

Unless most of your games will be with your friend, it would be a good idea to get two core sets. In addition to being a good deal for the minis, it also gives you extra core stuff which is always nice to have enough of. Especially dice.

You might also want to get the sort of ship that you think you would like flying the best. That might be just be the ships you find compelling. A Y-Wing is certainly a great beginner ship with its ion turret!

What about a y wing, I don't know the ships at all so I have nothing to go on.

As has been said before, what do you WANT to fly? What ships do you remember from the movies and think are awesome? Go with those kinds of ships, you'll have more fun. And later on, when you've played for a while, if you want to start in on competitive/tournament play then you can look at the other expansions to see what interests you.

What about a y wing, I don't know the ships at all so I have nothing to go on.

You will find that opinions on what's good, or worth it vary. Typically though you want to always buy ships in 2's. Another words, if your going to buy an interceptor, buy 2, if your going to buy a Y-wing, buy 2 of them.

This is a better practice then getting one of each ship as it will help to balance your collection out better over time. I agree that a Falcon and Firespray is a really great way to balance out a collection as well, though of course we all have our budgets. But again the cheapest way to improve your collection is with a second core set. You get 3 ships for less then if you bought them individually plus all the extra's (dice etc..). Well worth it.

What about a y wing, I don't know the ships at all so I have nothing to go on.

As has been said before, what do you WANT to fly? What ships do you remember from the movies and think are awesome? Go with those kinds of ships, you'll have more fun. And later on, when you've played for a while, if you want to start in on competitive/tournament play then you can look at the other expansions to see what interests you.

Its true, i've got two A wings that i bought before the core set as i love A wings and wanted a flight of four as my 'force'.

At the mo they are tricky to use well but it doesnt stop me flying them often as its more about recreating the film battles (or their style) to me than picking a killer list

I also like Y wings but only got two recently... slow tanks. Soak up a lot of damage, good for slowing the enemy down with ion cannons or a bit nasty with blaster cannons too as you can fire 360... but only at range 1-2

As far as choosing ships for tournament use, I doubt I will ever play tournaments, just not my thing, so all my ships are for play among friends, I will only be choosing in order to keep game play ballanced for the sake of fun.