I'm a huge fan. Suggesting albums can be really hard because Porcupine Tree have covered so much ground since their first album. However, since you're enjoying "Recordings", I would recommend asking to borrow "Lightbulb Sun". "Recordings" is mostly B-side material from the Lightbulb Sun era. My next suggestion would be to check out "Stupid Dream", the album before Lightbulb Sun, as some of the material from "Recordings" stems from that era (namely the full version of Even Less on the "Recordings" album). And then after you've checked out "Stupid Dream", look into "In Absentia". That's the album released after "Lightbulb Sun".
And as a bit of a side note, move backwards through the Porcupine Tree discography if you're a fan of "prog" material, and move forward in the discography if you're more a fan of a rock or metal sound. Hope that helps you.