Idukki (esp. Kutikannam) - Kerala. Dawki - Meghalaya. Nameri and Majuli - Assam. Garhwal (non famous places) - UK. Dzukou Valley Trek - Nagaland.
Simultala - Bihar (Bihar is home; when I went there years ago I just loved the quaint charm and temperate climate of this place; heard it's kinda blinged now). Latehar - JH. Dalhaujie-Chamba Trek - HP.
Green Route (was lucky enough to partially do it; banned now) and Doodhsagar rail track treks in monsoon - KA (and Hampi too - only if you go for 4-5 days min; and I loved Mangalore when it still has that small town charm). Stopped at lots of lovely unnamed places on a recent d day road trip BLR - Chikmagur - Murdeshwar - Goa - Velas (no couldn't see them) and back (via Mahabaleshwar, Belgaum) - KA/Goa/MH. I didn't like Goa much. Been there thrice. But after hearing about places to go to and things to do I guess I have been doing it wrong.
Lucknow city walk - UP (read about siege of the Presidency and then visit). Pachmarhi and then trekking deep inside Satpura - MP. Backpacking from Bilaspur to Bastar (when I was naively young; post teens :P) - CG. Mt Abu and Jaisalmer - RJ. Went on a day trip beyond Silvasa in DNH and the fields, rocky terrain, and small huts, tiny villages, small streams were things that take your breathe away. It was simple and perfect.
Murshidabad and Sundarbans (nothing else in WB cut it for me; not even Darjeeling which is really awesome) - WB.
Chilka Lake - OR. Pichavaram - TN (Dhanushkodi is next). Horsley Hills - AP (but I think it has more to offer than that).
There are lots of places to list. Most I can't name. But I can reach there again. The places where you just leave the bus or train and just go.