That's also my story. I spent countless hours reverse engineering software but stopped after going Linux-only. In fact I realized that reverse engineering was the only reason I'd been using Windows for a very long time.
I also remember many wonderful tools like PEiD (locating and identifying hash functions), hiew (hexeditor), RSATool (RSA cracking tool), FSG (file compressor). There was also OllyDbg and it seems that it's still actively developed.
Oh man, OllyDbg was excellent. I was never great at reverse-engineering, it was mostly a "change random jmps and hope it works" thing for me, but it was exciting. Nobody I knew had credit cards back then, and I was a teenager, so I couldn't pay anyway, but I'd get shareware I don't use just to see if I can crack them. I'd delete them afterwards.
I once created an "uncrackable" crackme (in Visual Basic 4, no less!) that had a part of its code encrypted with RC4, and the license key was the decryption ley.
I also remember many wonderful tools like PEiD (locating and identifying hash functions), hiew (hexeditor), RSATool (RSA cracking tool), FSG (file compressor). There was also OllyDbg and it seems that it's still actively developed.
Ah, memories.