Ultralight windbreakers?

Sam Oudekerk wrote: It’s impossible to beat a Walmart frog togs rain jacket. They are the lightest, cheapest, and most waterproof (plus no worrying about a DWR wearing off). None of these shells are durable. Don’t wait your $ like I did before I found the best.

I opt for my frog togs over my arcteryx hard shell 99% or the time when I’m not expecting extreme abrasion.

+1 for the miracle Driducks / FroggToggs. Light, breathable, waterproof and cheap. Con: flimsy and poor-fitting, and the jacket’s hood isn’t great. I wish I had a knack for sewing.

Montbell tachyon anorak. Stupid light. More durable than it appears but do not bushwhack or chimney with it. 

I'll give another recommendation for the Helium 2. OR also sent me a new one for free before I could even send in my old one with a busted zipper.

Dave Olsen wrote:

It that Tyvek noisy like the house wrap version?

It's the same material so I would say yes. It doesn't bother me though.

Brandon Ribblett wrote: I have the mountain hardware kor preshell and it sounds perfect for you. Packs to the size of a small apple and breaks wind well and shields light rain. 

The OP said it had to pack down to the size of an orange not an apple

Jackets:
Patagonia Houdini - Light, blocks a great amount of wind, packs small. This was part of my "cold" weather climbing clothing. Baselayer, fleece jacket, houdini. Baselayer for hiking in, fleece for climbing in, houdini for belays or blocking wind when climbing and its not chimneys. I do my best to avoid taking a puffy jacket considering how much space they take up.
Black Diamond Alpine Start Hoody - A bit heavier, but more featured wind jacket. I have been using it recently instead of the houdini. Does not pack down as small, but small enough for me.
NW Alpine Eyebright - Cuben Fiber (dyneema composite fabric) + WPB membrane. UL WPB Rain Shell. Expensive, no stretch, not really available right now. Packs down very small. Very light. Breaths fairly well for a WPB Shell. Obviously blocks all wind. Maybe not quite long enough. Doesn't come with its own stuff sack / doesn't stuff into its own pocket. I sewed a small stuff sack slightly larger than a houdinis stuffed size. This is what I will take with me when it seems like weather or heavier wind is a real possibility.
OR Ferrosi Hooded Jacket - Blocks just a little wind. Not a brushed inside so it feels cold against the skin. Has decent durability and stretch for the weight, so I have sometimes put it on top of fleece or puffy for more burly climbing like OW and chimenys as a sacrificial barrier.
---------- I have not used, but have considered -----------
Patagonia Alpine Houdini - Houdini with added weather protection.
RaidLight Ultra MP+ Jacket - WPB w/ 4-way stretch. Hmm.
... honestly the Houdini, Alpine Start, and my UL rain shell work so well I have not put a lot more thought into wind or rain shell jackets. I have a ski shell with Polartec NeoShell that works for that too, so I've pretty much got my use cases covered.
Montbell Tachyon Parka - UL wind shell, maybe too light for the low durability. A very light option that still has a hood and front zip.
Montbell UL Stretch Wind Parka - UL wind shell, slightly heavier, some amount of stretch.
Outdoor Research Helium II - UL rain shell. A strong contender if you are looking for a good shell jacket for rock climbing that packs pretty small.
UL MYOG Cuben - Make one out of cuben fiber or have someone else make it. There are several small UL gear manufacturers out there who would do it. No or 1/4 zip pull over would be really really light. Block all wind. No breathability.

Pants:
Climbing wise if its cold and windy instead of having wind/rain pants I currently just use some Arcteryx Gamma MX Pants. Light fleece lining. I love 'em. Gets sweaty on the hike in often, but oh well.
Patagonia Houdini / Alpine Houdini - Considered getting several times.
UL Cuben WPB pants - ordered some used ones, tried on, crotch fit (rise) was horrible, no crotch gussetting either, re-sold. Don't know brand. Packed down to about the size of a packed up houdini. If they had fit better I would have considered keeping them as a just in case of bad weather option.
----------- I have not used, but have considered ------------
Montbell Tachyon - UL wind pants, check youtube reviews, UL hikers seem to generally consider these to be too fragile. 7d.
Montbell Dynamo - UL wind pants, but slightly heavier at 12d. UL hikers seem to agree these are a favorable benefit of increased durability compared to the Tachyon, worth the weight increase. I was strongly considering getting these, but stretch WPB tempted me away, and I ordered something different.
Montbell Versalight - UL rain pants, still pretty darn light. 10d + 2L WPB Gore Infinium Windstopper.
OR Helium Pants - UL, but relatively heavy as far as UL wind or rain shell pants go.
Ultimate Direction Deluge - UL, but I don't think they posted weight is accurate. 20d sil coated nylon should be a lot more than 10g heavier than the Montbell Tachyon.

Ordered, but not tried yet:
RaidLight Ultra MP+ pants - ultralight WPB w/ 4-way stretch. Ordered to have as a light wind/weather blocking layer for trail running or hiking in advance of a Grand Canyon Rim-2-Rim trip. Most wind and rain shell pants I have seen have zero or minimal stretch, so this seems like a nice option. Or if they do have good stretch they are much much heavier. We shall see. If it works well I may fiddle with ways to use it climbing too.

highaltitude, no question the item for you is the MH Kor preshell because, as we're advised above by Brandon, it breaks wind well.