I was wondering about 1. e4 e5 and 1.d4 d5 openings - would you recommend exploring some of these? I'm not enjoying being squashed as black any more and thought I'd make a longer term plan to learn a (very) few classical openings instead. I wondered about French (winawer?) but thought I try a complete new tack (why swap an early d6 for an early e6 ?!!)
My first thought was, I don't know how long you've been getting back into the game, but I'd leave the job of taking on two or three whole new opening systems for a bit. You're probably better off getting your eye in again on more familiar territory, before taking on a bunch of new theory (and indeed a new style of playing). But if you fancy it, go for it!
I certainly think going classical makes a lot of sense: I've told people to do it, and a couple of people have told me to do it... and I've tried it, but I don't think it suits me. I don't know if would suit you: 'suiting' isn't just style and temperament, but also time for study.
I always like to find a player who has the same repertoire as I want to play. Modern GMs tend to be a fidgety lot, but I remember digging out some of Nigel Short's games to study how he handled the Black side of the QGD Tartakower. I don't know who I'd pick as an archetypal defender of 1.e4 e5: Lasker? Unzicker? Korchnoi?
I don't know a good book to support playing 1...d5 if you fancy playing it; there are several repertoire books around, but I don't know them. Aagaard and Lund's book on Defending 1.d4 is based on the Tarrasch, and gives suggestions against all the non-2.c4 non-1.d4 systems as well. Sadler's book on the QGD I thought was excellent.
There's a fine book by John Emms on playing 1...e5 as Black against 1.e4; although the weight of variations is daunting it is thorough, practical and gives a couple of alternative lines for the reader to choose at many points. I never know how to use books like this: I feel it needs a 'Coles' Notes' version to accompany it, something to boil it down to a core of stuff I can learn.
You might like to have a browse of Nigel Davies' stuff (I can't now
find a lot of the pages I used to point people to since he moved
websites); he spent
time in Israel working with ex-Soviet GMs and felt rather keenly the
lack of a 'classical education'; he began to play with the centre and
moved away from the Modern towards playing 1...e5. He's also produced a
repertoire book for Black about 1...e5.
Advice is worth what you pay for it.