History
When the format first had a separate list from Vintage everyone feared the dreaded "Combo Winter of 2004" that never came. Deck lists were untuned and just not strong enough to compete in the metagame; many of which ran four Diminishing Returns, Helm of Awakening, and Goblin Charbelcher which were terrible in the metagame. This lead combo to sit on the backburners of the format with its prized deck Nausea created by Evil Roopey in the open forums. Nausea was an alright combo deck for its time but was never broken or strong enough to break through the barriers of tier two.
About a year later a deck that was based on Ill-Gotten Gains came out called "Iggy Pop" created by Michael Bomholt (Bomholmm), this deck with the addition of the newly printed Infernal tutor was strong enough to take down those barriers. "Iggy Pop" did very well at large events such as GP Philly and Worlds. "Iggy Pop" rained champion of Tendrils based combo for a long while, there was other combo around but wasn't very tuned. About six to eight months later the sets Coldsnap and Timespiral were printed.
Coldsnap and Timespiral gave combo cards necessary to handle control and give combo the edge it had been waiting for all along. The card Rite of Flame was printed it was the second best 'Ritual' effect in the game since Dark Ritual. This card allowed combo to "combo off" more reliably and quickly in the opening turns of the game. The next card to help combo dramatically is a card called Empty the Warrens, this card is was put combo over the edge. Combo could now run multiple win conditions that killed in a timely manner, dodge hate cards like Meddling Mage, and kill with opposite cards to avoid hate for the other win condition.
A deck called "The EPIC Storm" created by Bryant Cook (Wastedlife) would soon break the surface using cards from these new sets. "The EPIC Storm" and "Iggy Pop" would soon start competing to be "the combo deck" of the format. Soon after this "The EPIC Storm" took first place at The Mana Leak Open in Stratford Connecticut piloted by its creator. "The EPIC Storm" would soon break another barrier of being the first ritual based combo deck to break the LMF in over two years.
With the release of the next set Planar Chaos combo gained another powerful tool in the card Simian Spirit Guide, all combo decks alike could abuse it but very few did. With Simian Spirit Guides addition to combo, Belcher lists flourished out of nowhere and a team from Canada would make a list called "CRET Belcher". This list was piloted to a second place finish at Kadilak's Dual Land Draft Three in Baldwinsville New York by Brian Diefendorf (Ewokslayer).
Then Flash Happened.

The Decks
Iggy Pop
The EPIC Storm (TES)
CRET Belcher
Spanish Inquisition (SI)

Combo Summer

Many people believe that these combo decks will dominate the metagame in the summer of 2007, much like the hype of "Combo Winter in 2004". But is this hype? Combo has been performing the best it has ever been in the format currently, for the first time we have a format that somewhat resembles a rock, paper, scissors format. Is combo summer healthy? Many believe that combo being this powerful is bad for the format and will make players withdraw from Legacy. I believe this is the healthiest Legacy has ever been. I said it, "Combo is healthy for the format." With combo in the format, it brings the best deck in the format (Goblins) down to reality and shoves it on its ass. While combo is for the first time at its peak, it's not overly powerful. The "Aggrocontrol" deck of the format still goes near 50/50 with each and every one of these combo decks.

The Big Question
Will "Combo Summer of 2007" happen? Combo now has all the right tools to be successful for the first time in the format. Many people believe that combo is unhealthy for the format and should have certain pieces such as Empty the Warrens or Lion's Eye Diamond banned. While I disagree to this due to the fact that it allows the format to evolve and make changes much like a healthy format should, many other people believe the opposite. The format has dealt with many powerful things and has adapted to deal with them such as Goblin Lackey and Flash. It's not like either card mentioned is unstoppable or utterly broken to the point a large part of the metagame is unplayable. Lets face it, little Timmy's elf deck wasn't competitive before Empty the Warrens; why would it be now? Combo is still a small portion of the metagame, and will always remain a decent but small portion of it.

Thank you for reading, and please discuss.