You might also consider getting balance, which has the key built in - that way, if you have your audio interface you always have your license (you can put the license on a key and balance).
the upgrade to reason 6.5 from R5/R1.5 is $169.
If you look around, you can get Balance for just under $350 and because you own R5 and/or R1.5, the balance purchase gives you a free upgrade to R6.5 - which effectively means getting Balance for $180, not to mention that you could sell the essentials license and perhaps offset the cost even more.
HP Pavillion DV7T-3300 Laptop | i7 Q720 @ 1.6 GHz | 4GB RAM | Win7 Pro 64-bit
m-audio Axiom Pro 61 keyboard controller || iPad2 | RetouchControl DUO | TouchOSC | LoopBe30 MIDI
m-audio Mobile Pre USB (original) audio interface | ASIO4ALL || RØDE NT-3 mic
Reason 6.5.3 || Pulsar | Saturation Knob | Rough Rider | TSAR-1 | Uhbik-A | Re-Tron | Polar | Echobode | Uhbik Q | Uhbik F | Morfin XF | Uhbik S | Uhbik D | Uhbik G | CV Suite Line Processor | wbl5515 | Uhbik P | RE-2A | Radical Piano