Ok, time for a trek back through nostalgia time for me:
I don't have some of the older ones except for the 6850 Mobile Rocket Transport, although I have at least one of everything you listed below the 6805 set. Maybe I should try to get some of those really old ones from the original 1979 classic space lineup.
Aside from the SP Striker, these are some others I really like. I have two copies of each of these since they all have great parts:
6915 Warp Wing Fighter: newer set but excellent design, my second alltime favorite, looks a little like a Pyro GX
6894 Invader: great overall small fighter
6923 Particle Ionizer: unusual concept and has quite a few things packed into it
6958 Android Base: very roomy and feature packed for the size and price and comes with a great AAA vehicle
6984 Galactic Mediator: has some shortcomings but the overall shape is great
6939 Saucer Centurion: very cool mechanism for unloading the rover
6987 Message Intercept Base: the mother of space bases, has tons of stuff, although not quite perfect
6986 Mission Commander: this one actually has a lot of flaws but it looks very cool and is an outstanding source of parts
I stopped just about the time that I was about willing to sell a kidney for the monorail set that had just come out
If you are talking about the Futuron 6990 set, I'm still really trying to acquire one of those. Problem is they go for close to $400 new on ebay these days.

I might settle for the newer Unitron monorail, which is better in some ways and worse in other ways, although even that costs close to $300.