Below is a collection of my favourite Harry Potter and Twilight fanfiction. Hope you enjoy them as much as I did.
TWILIGHT
A Rising Sun by A Seagull In Iowa
http://community.livejournal.com/aseagulliniowa/tag/series:+a+rising+sun
Summary: BD AU - The Denali clan arrive two weeks early for the wedding, bringing mischief and trouble in their wake. But Tanya and Irina are the least of Bella's problems. When the Volturi and the werewolves both remind the Cullens of their promises, Bella realizes that she will ignite a war, no matter which choice she makes. What no one will realize until too late is that Aro wants something - and he will do anything to get it. Not Yet Complete
HARRY POTTER
Unlocking Harry Potter by Sarini
http://www.fanfiction.net/s/2529243/1/Unlocking_Harry_Potter
COMPLETE! PostOoTP, PreHBP. Severus has been having dreams, dreams so real they feel like memories. What is his mind telling him? Severitus with a twist. SLASH HP? MA15+
Finding the Key by Sarini http://www.fanfiction.net/s/2579033/1/Finding_the_Key COMPLETE! Sequel to Unlocking Harry Potter. No HBP. Severus Snape is no longer a spy and has officially acknowledged Harry Potter as his son. Just when it looks like things are getting better for Harry... SLASH HPCW .. !WINNER 2006 GOLDEN QUILL AWARD! MA15+
Closing the Door by Sarini http://www.fanfiction.net/s/2617038/1/Closing_the_Door Summary: Five years after Finding the Key life has settled down in the wizarding world... and then Severus finds the solution to the problem he's been working on all that time, and people start dying again, and this time Harry Potter is unable to save the wizarding world from the trouble they find themselves in. MA15+