There's a lot to mention so here are a couple of mainly guitar-based albums I have heard that I think are worth checking out :
For the Django style gypsy jazz, I would recommend Rosenberg Trio. They have a collaboration with Stephane Grappelli (called "85 and still swinging") which is terrific. Rosenberg also have several live albums (Samois, Vienne, NorthSea) but I think the best recorded ones are the studio Seresta and "Ready and Able" albums.
Birelli Lagrene is also a gypsy jazz genius, and his "The Complete Gypsy Project" is a great recording of Django style "manouche jazz" playing. He has some acoustic albums and electric jazz guitar ones. I like his "Standards" and "Virtuosity" album quite a bit.
You mentioned you like Howard Alden. Definitely listen to his albums with George van Eps (13 strings, Hand crafted swing, 7 and 7). His albums with Jimmy Bruno (Full Circle) and Bucky Pizzarelli (In a Mellowtone) are also fantastic.
Jimmy Bruno (Sleight of Hand, Solo, Burnin'), Bucky Pizzarelli and Jimmy Rainey (The Influence) are also great recordings of master straight ahead jazz guitarists.
For Solo guitar, some of the best recent records are by Martin Taylor. He also has an album he did with Grappelli (Reuinion). Also check out the "Tribute ot Art Tatum", "Solo Jazz Guitar", "Portraits" and "Kiss and Tell" albums.
If you dont mind a bit of singing, the recordings of the Susie Arioli band have
a lovely hollowbody acoustic jazz guitar sound mic'ed uplclose on albums like "That's for my baby", "Pennies from Heaven" and "It's Wonderful".
Joe Pass has many great albums, not all are good because many of them are live albums, but his Virtuoso 1-4 albums are a must for any jazz guitar collection.
Gene Bertoncini's Body and Soul is also a very well recorded solo jazz guitar album with many standards played in the chord melody style.
Two of my favourites as Johnny Smith and Tal Farlow. Johnny Smith's "Sound of the Johnny Smith Guitar" is great, as well as his album with George van Eps "Legends" which is a good recordings. Roost has a compilation of all his studio cuts. His "Moonlight in Vermont" with Stan Getz is a masterpiece.
Tal Farlow's "Cookin on all Burners" and his duet albums with Lenny Breau "Chance Meeting" are cleaner recordings than his earlier stuff.
His Verve recordings are classics but not the cleanest quality with a bit of hiss.
Ulf Wakenius' "The Guitar Artistry Of Ulf Wakenius" and Ed Bickert's "The Guitar Mastery of Ed Bickert", Joe Dorio "We Will Meet Again" and Jim Hall's "Concierto" are quite good.
Wes Montgomery is another must have. Bumpin', Dynamic New Sound, Full House, Finest Hour are all pretty well recorded. I picked up his complete Riverside recordings 12 CD set which has most of his great tracks.
Lee Ritenour has some well recorded albums, solo (WesBound) and with Fourplay, in the modern smooth-jazz style, if you dont mind the keyboards and slap bass too much
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Of the new guys, Mark Whitfield (7th ave. stroll, True Blue, Marksman) has a nice straight ahead jazz sound. Russell Malone's Black Butterfly is good.
As tonym mentioned, there was a Grant Green thread last week, check out his albums mentioned there.
These should keep you in six-string bliss for years to come
Enjoy