There's far too many of these things now for us to give you any kind of a recommended reading guide unless you cut off at about post #5...
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But, for what it's worth... top picks:
Questionable Content, Girl Genius, Paradigm Shift, El Goonish Shive, Freefall FOR THE LOVE OF GOD FREEFALL (and, I guess, Kevin & Kell though I never got into it myself), Elf Life if it's still going (I gave up following...), 8 bit theatre, Roza the Cursed Mage, DMFA, 2Kinds, Slightly Damned, The Meek, Lackadaisy (the last two if you're patient)... *breath*
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Honourable mentions for various reasons (ended their run, gone on indefinite hiatus, eventually lost interest or ability to hold onto the story - but before those events, they were well worth keeping up with):
Unicorn Jelly et al, Goats, It's Walky! et al, College Roomies From Hell, Kid Radd, Hana is Not a Boy's Name, Order of the Stick, Misfile / Venus Envy / The Wotch (if you start at the beginning then abruptly stop around 2006 in the archives because the stories terminally foundered and became hollow shells around a dwindling core of morbid transsexual voyeurism, you'll mirror what I did "live"), Bobbins / Scary-Go-Round and the follow ups, Dresden Kodak
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See, just off the top of my head, that's 26+ examples I've been able to give you just in terms of good quality continuing story comics, and I've actually missed out a few classics, I'm sure - and haven't even got into semi-story/semi-gag, or multiple short-story strips like Sandra and Woo, Housepets!, SSDD, etcetera.
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Your hit rate will probably be almost as good if you just load up a few webcomics ranking sites and start clicking amongst the top-50s at random. If the internet has shown us anything, it's that competent, inventive story writers and artists are ten a penny and just need an outlet, given that serials as good as (IMHO) almost any sweatshopped costume-hero pulp releases rise and fall like seedlings in the forest.
The above ones are just those of which I've had the fortune to get to know over the past 12 years or so (since I saw my first one), the top list is largely those I still follow, because they're worth taking time out of your week to keep up with.
Heck, I even bought the first three printed volumes of Paradigm Shift, and I can rarely afford to buy graphic novels. Last time I stretched to that it was Nausicaa, for heaven's sake.