Well, if you want to use your pod with an amp, and want the "warmer" tube sound, you should look for something that has more headroom -- a nice clean, 30-50 watts.
What you won't get is great tube poweramp overdrive (which is sought after), unless it is at high, high volumes. This is the tradeoff. Lower wattage amps like
a THD univalve, will overdrive at lower volumes, and your POD would help drive it, but what you would get is a mix of your pod sound and amp overdrive sound -- probably not desirable, unless you only use clean sounds from your pod.
In the $500-600 range there are things like
the Fender Blues Deville/Deluxe. Great clean channel, not a very good gain channel (it is a 2 channel amp). Peavey makes
a classic 30 and 50 that would work too.
If you are willing to look used, I would say the best deal would be on a Silverface Fender bassman head. These are excellent values, usually between $200-400 (would need to buy a cabinet), take effects/pedals well, and if the volume is raised, has a great crunch. Kinda the best of both worlds. ALso, they are simple curcuits and are point-to-point -- which means they are easy to fix, are generally reliable, and easy to modify if needed. I love mine, and often run my Rocktron ProGap (early modeller) through it. Sounds great. Look for 50 watt versions from the mid to late 60's. Avoid 70 watt and/or master volume ones from the 70's.
There are also lots of lower and higher wattage amps that are great for recording, but I left them off the list b/c they are either for recording overdriven tones (Silvertones,
Fender Deluxe reverb, Univalve) or are out of your price range (Vox AC30s, Hiwatts).
I don't use a compressor in my guitar signal chain. Never liked them there. But, I have used one in the mic chain to reduce the chance of digital clipping into a computer. Unless the POD lets you insert an effect before the cabinet sim and/or power amp I would probably put it up front.
Also, it is SS but Tech21 makes a product, I think it called a power block or something, that is a powered cabinet with no controls. It is made for use with modellers.