If you had about $600 to spend on an amp, what would you go for? Just looking towards the future.
1998 Gibson Les Paul Standard
1992 Ibanez RG550
1978 Marshall JMP 2203
What type of music?

I play Death Metal and my line 6 spider III works for now. Which was around $500

once I get more money I'll probably go for mesa boogie or krate
look for a used marshall jcm 800-900 they can be had for around that price if you know where to look
2008 M.I.A. HSS Strat
Marshall JCM 900 50w Dual Reverb
yuk valvetronix, i have to say mate, unless you plan on gigging etc, 100w is unnecessary, and try to get something all tube