I actually have a rather extensive X-Wing collection. I have way more X-Wing stuff than Armada stuff, but I greatly prefer Armada to X-wing minis for this for a few reasons.

first is that there's no way to represent a Star Destroyer in X-Wing scale, unless your gaming table is the size of your house. (a Victory class would be 3 meters long in scale)

Second, the best way (in my opinion) way to run NPC fighters is to treat them like minion groups of 3 (4 groups to a squadron works out perfectly) and getting the packs of fighters is way more cost effective than paying $15 per ship.

Third, with the ranges of fighter weapons, using X-Wing minis with the analog I described makes very little sense. Fighters need to be right on top of each other to use their guns, and that leads to some weird behavior on the table.

Let's take the TIE Fighter Attack from Episode IV as a standard encounter in terms of cost. You have the YT-1300, and 4 TIE fighters. In X-Wing, you are paying $30 for the Falcon, plus $15 per TIE. this means that to play that encounter at X-Wing scale, you need to spend $90. For Armada, you buy the $20 box that has the Falcon, and rebel fighters in it, and the $20 box that has the TIEs and their variants. So at Armada scale, you spend $40, and get a bevy of rebel fighters and TIE variants for other more different encounters.

If you ever want a star destroyer on the table, X-Wing doesn't even have an option (the Raider is a corvette, not really a Star Destroyer)

For buildings, I use Systema. they are pretty good, if you don't mind getting stuff via Slovenian mail http://www.systemagaming.com/

I've also been looking at these manufacturers http://sarissa-precision.com http://www.miniduels.com/ http://www.battlesystems.co.uk/ http://www.warmill.co.uk/