Radio tech has come a long way in the past couple of decades. While you can still purchase radios on the 72MHz band(the band reserved for aviation), they are few and far between. Most radios now days are on 2.4GHz and are incompatible with the old stuff.
My recommendation would be to figure out how many channels it would take to fly the most complex plane you have and buy something that can handle it. One thing to look at is how the servos were set up with the control surfaces and throttle. I know many of the older designs used bellcranks or torque rods to move the ailerons. With the modern radios, most use a servo on each control surface and mount the servo close to that surface to keep pushrods as short as possible
Something else to be aware of is that a servo isn't just a servo any more. There are many different types to choose from:

• analog your standard servo. lowest cost and pretty much what you are familiar with
• high torque made for heavier loads while normally in a standard sized case
• digital similar to the standard analog except it has a more precise positioning
• brushless similar to the digital except for the motor. Unlike the digital and analog types, the drive motor uses a drum over the armature instead of a couple of contacts
• S-Bus these are programable and much more expensive than any of the others

There are also servos that mix various features of the types above. I use a high torque digital servo to control the rudder on a 1/8th scale hydroplane but I use a standard digital for the throttle. Depending on the battery voltage, the high torque servo I use will give either 270 or 340 oz-in of torque.

As far as what to buy, you might want to stick with the brand you had since the transmitter would use similar protocols to what you're already used to. I would recommend sticking with a name brand and buy everything you need initially from that manufacturer so you don't have to worry about compatibility or having to reorder the pins on the servos to get them to work with the receiver you buy. One word of caution, however. There are people out there(and here in the forum) that will tell you that you need to buy this brand or that because it's what they use. Others will tell you to save money and buy a bargain priced system because they've had good luck with it. I personally use Futaba and, even though I use it, I won't say to go with it UNLESS YOU'RE COMFORTABLE WITH IT!!!! Buy what works for you as not every manufacturer or radio works for everyone
One last thought, WELCOME BACK